Once upon a time, there was a man who thought love was a maths problem.

“Love is a capricious spark, a miraculous whirlwind,” one of his blog posts began, sarcastically. “It is found by following ancient prophecies, embarking on dangerous quests...Something like that, who knows. Anyway, it sounds like finding a girlfriend was crazy hard before computers!”

The man’s name was Jacob. He is currently 32 and works in finance, creating software that helps banks comply with regulations. He has dark curly hair and a beard, a left eyebrow that’s often raised and, in his own words, a “dad bod”. His self-deprecating streak is tempered by optimism. “Growth mindset” is one of his favourite phrases. As in “I’m still not bisexual, but, you know, growth mindset.”

For most of his life Jacob dated only when he’d received clear signs of encouragement from one of the many women he found beautiful or fascinating. In 2013 he moved to New York from North Carolina. Thanks to the volume of people using dating apps, it was suddenly possible to spend each night of the week with a different woman who was already intrigued by his online persona. There was the cheesemaker. The fashion designer. Three different med-school students. Jacob liked them all. On each date, he holidayed in another person’s world and learned something new.

But cumulatively, the experience was overwhelming. Jacob knew he wanted to get serious with someone, but he found it hard to weigh the merits of each of these potential partners against each other. So he did what he knew best: he made a spreadsheet. He called it “How to Choose a Goddess”. When he described this to me, some of the calculations lay beyond my comprehension. But my more quantitatively minded friends seemed impressed when I rattled them off.

Jacob wanted to work out which of the women he’d met online would make the best life partner. He started by listing ideal qualities for a girlfriend, then weighted them as objectively as possible. Great sex, for instance, was worth roughly a third of great conversation, since people typically spend less time doing it. Other categories were peculiar to him. Jacob outlined 15 attributes in total, hoping that by isolating his requirements he could compare them in a systematic way. “Status – friends admire her”, “Will be smart, dedicated mom”, and “Emotional crush” were worth 5, 9 and 6 points respectively. But Jacob still didn’t know if his back-of-the-envelope estimates were right.

At one point he considered using pairwise ranking to assess his hierarchy of priorities and advanced statistics to determine the relative importance of Goddess Qualities. He’d learned these tricks in a business-school class about pricing goods. Ultimately Jacob chose a simpler approach. “A guesstimated number is better than not using numbers at all”, was his motto.

He then scored each woman attribute by attribute, multiplied those numbers by their weights and added the results to get a final score. But there was a problem: Jacob didn’t know what counted as a high enough score to indicate that he should stop dating and settle down. So he devised his own spin on the “Secretary Problem” – an equation typically used to decide what percentage of potential candidates a person should interview for a job. (The classic solution: the greater the size of the pool, the closer the answer tends towards roughly 37%.)

It was strange, but I envied him. All the wine-fuzzy conversations, the uncertainty and speculation, the obsessive close-reading of text messages had been reduced to neat digits. Jacob wasn’t objectifying women by rating their looks, as a pick-up artist might. His scores measured compatibility. And he wasn’t claiming that his system was perfect. The measures in one category, weighted very highly (15!), were entirely speculative – Jacob’s estimate of how much his dates admired him. But despite these imperfections, data were a better guide to ending up with a good match than the conventional wisdom: follow your heart, stick it out when things get tough, love will endure. Emotions were just mysterious cocktails of oxytocin and phero­mones, Jacob believed, that could leave you on cloud nine or in jail depending on the luck of the draw.

Jacob is just one of a growing number of people seeking inspiration from business schools rather than poetry in the quest to find the right partner. This hard-headed attitude is evident in the practical turn that romance’s ardent lexicon has taken in recent years. We look for partners, not soulmates. We avoid deal-breakers. “Are you in the right headspace to receive information that might hurt you?” reads a recent meme, advising people to ask loved ones for consent before making demands on their emotional labour.

As Carolyn Yates, a writer and editor in Los Angeles, recently told me, romance is “figuring out in an efficient manner what works between people, just as much as being swept away in feelings”. Yates is polyamorous, queer and takes the pronouns they/them. Their relationships often shift fluidly between romantic, platonic and sexual and they go on a lot of first dates. With partners new and old, Yates takes copious notes in a planner on everything from conversation topics to what they ate and whether the date entailed sex or bondage. The note-taking does feel a bit like work, says Yates, but they reckon it makes them more considerate.

Yates is not the only one who has found that a business-like approach to relationships has made them kinder. Take the polycule – that’s a relationship constellation of three or more people – near Chicago, which recently used Excel to plan an orgy. The day before, participants entered their pronouns, likes, dislikes, boundaries, hard stops, aspirations for the orgy, std status and sexual preferences. This clarity made the experience that followed more “comfortable”, according to one participant.

One New Zealand couple deployed Agile, a project-management system that companies such as Microsoft and Lockheed Martin use to streamline processes across teams, in their marriage. The goal was continuous improvement. They held monthly retrospective meetings, where they reviewed personal successes and failures and set “action points” for the next month-long sprint.

All these people are trying to optimise the process of acquiring a partner and maintaining a relationship. Optimisation grew out of attempts to solve real-world problems with mathematical techniques. People are most likely to have experienced the effects of optimisation in their workplace. Management consultants, for example, used statistics to help companies perform better. In order to maximise a variable, such as profit, they manipulated different inputs, such as the costs of inventory and number of employees. Today, optimisation is regularly applied closer to home in exercise, sleep and diet. If these can now be tracked, quantified and streamlined, perhaps love and sex can be too. Aren’t relationships simply interactions that, with tweaking, could become more efficient and less prone to friction? In other words, aren’t they just a business problem?

For centuries marriage was an economic transaction, a means to exchange property and secure its transmission across generations through the creation of legitimate heirs. In some parts of the world it still is. In the West, love was the domain of pre- or extra-marital affairs: unrequited, temporary, romantic. This last word entered common usage in the Middle Ages in stories about chivalric heroes on quests to woo attractive maidens they encountered on their journeys and then abandoned as the plot moved on. It later became associated with novels (which, in some quarters, were considered a danger to impressionable women). It was only during the Industrial Revolution that romance was injected into marriage. Before then, marriage was essentially a contract between two families. With the rise of wage labour and an industrial economy based outside the home, the domestic sphere was annexed for romance. In some countries this transition happened much later. Love has been allowed to play a larger part in marriage choices of people in China only in the past 40 years. In India, arranged marriages are still the norm, although young people increasingly make the final determination.

The current trend for maximising returns in love, then, is a reversion to the original pragmatic approach. Models of corporate efficiency now govern large swathes of romantic life. About 65% of same-sex couples and 39% of heterosexual couples who got together in America in 2017 met on dating apps, which use algorithms to match them. Jacob was simply taking matters into his own hands. Some, of course, hated this approach. “Can you see why reducing human connection down to a single real number 1-10 is bad? Look in their eyes. Sing songs together. Dance,” commented one person, after reading about the spreadsheet on Jacob’s blog.

People who use spreadsheets, charts and planners to manage their love lives are different from the majority only in their conscious embrace of a fundamental truth – that relationships are transactions, and the work involved in creating and maintaining them is a form of labour. It’s a surprisingly democratic position, much like work itself. The relationship optimisers I interviewed have little in common with each other – they were secular and religious, writers and engineers. Or rather, they often had only one thing in common: they ended up wondering whether more than one relationship was optimal for modern life.

The traditional nuclear family has begun to look dated for many young people. Marriage rates have declined 8% in America in the last ten years (lots of couples no longer bother with a ceremony). Home-ownership is increasingly out of reach for millennials and rent becomes more manage­able when split multiple ways. Raising kids often takes more than two people, whether the additional help comes in the form of nannies or relatives. Is co-parenting in a throuple (a relationship involving three partners) really so different? Some 5% of American relationships are consensually non-monogamous, according to research published in 2014 by Chapman University and the University of Michigan. In 2017 the Journal of Sex and Marital Therapy noted that one-fifth of Americans reported engaging in consensual non-monogamy at some point in their lifetime. This proportion was higher among the LGBTQ population, but was otherwise constant across age, education level, income, religion, region, political affiliation and race.

Jacob was standing in the stairwell outside an apartment, half naked and holding his clothes, when he first considered dating two people at once. A few minutes before that he’d been in the flat of a classmate on his MBA programme at the University of North Carolina. She had invited him over to work on a project, then walked out of her bedroom in her underwear. Jacob was startled. His first impulse was to undress, too. Then he remembered that, in a more sober frame of mind, he’d weighed the pros and cons of cheating and decided against it. Grabbing his clothes in a panic, Jacob fled.

At that point Jacob had been dating a woman for two years who lived thousands of miles away. He met Natasha – this is not her real name and she declined to comment for this article – in Israel, where Jacob’s parents live, when she was visiting from Russia. Jacob says he knew he was in love when they stayed up one night solving probability problems in their underwear. Natasha was on track to becoming a hedge-fund quant. Jacob was applying to business school. Both wanted marriage and kids and to move to America.

Jacob knew that cheating was wrong because lying was wrong. Nonetheless, the situation he found himself in with his business-school classmate seemed perverse – he was rejecting a beautiful and interesting human being who had improbably chosen him, in order to date someone whom he could see only occasionally. A solution dawned on him. The next time he and Natasha met up, Jacob popped the question: what about an open relationship? As it turned out, she had been planning to ask him the same thing.

After graduation, Jacob and Natasha both got finance jobs in New York. They moved in together, signing a lease on a one-bedroom, 18th-floor apartment in a glass tower. They decided to stay open, dating others while loving each other.

The American utopians who coined the phrase “free love” in the 19th century saw their collective approach to sex as part of a political programme that would result in the destruction of capitalism. With non-monogamy, “the frost and ice of selfishness and exclusiveness melted,” wrote one member of the utopian Oneida community, which was established in upstate New York in 1848. (Mormonism had been founded not far away only 18 years earlier.) The community believed that “complex marriage” was divinely ordained. Everyone slept with whomever they liked, but if any pair became too attached, a council of their peers intervened to prevent possessiveness. Child-rearing was collective too. Children were educated never to say “me” or “my” but always “we” and “ours”.

More than a century later, a subsequent generation of free-love advocates – hippies, radical feminists and gay liberationists – drew inspiration from Oneida. These groups believed that monogamy produced individualistic family units, in which unequal gender roles reflected inequality in society at large. Love without limits, it was argued, would dismantle patriarchy along with capitalism.

By the time Jacob opened up his relationship, many of these communities had drifted away from their utopian principles. Today Oneida exists as a manufacturer of high-end homeware. By the 1980s Kerista, a polyamorous commune founded in 1971 in San Francisco, had become a thriving distributor of personal computers.

Today, critics of monogamy rarely argue that it is too individualistic. On the contrary, monogamy is considered insufficiently tailored to the pursuit of personal happiness. “We spend longer than ever selecting the right partner and tie up ever more of our hopes, dreams and identity in the partnership,” Jacob wrote in one blog post. “Almost inevitably, the relationship fails to fulfil its promise.” Monogamy was a conformist approach to love that pre-supposed sacrifice and compromise when perhaps none was required. Non-monogamy, on the other hand, allowed participants to fulfil their needs for romance, friendship, professional support and sexual excitement with different partners. Experimenting with different forms of relationships allowed individuals to discover what worked for them and to customise their ideal arrangement.

The current emphasis on non-monogamy as an expression of personal choice has attracted criticism from some of its historic advocates, who argue that polyamory and other alternative relationship styles should be used to build community and subvert existing power structures. According to Eleanor Wilkinson, a feminist academic, non-monogamy is often presented as a “watered-down, apolitical vision”. Optimising relationships is just another facet of capitalist individualism.

New forms of relationship necessarily make inventive use of the materials that society provides them with, so perhaps it’s inevitable that they have certain corporate overtones. Because non-monogamous relationships also lack legal protections – group marriage is illegal in many countries, and in America you can face legal employment discrimination on the basis of relationship style – participants have to get creative. One option in America is for groups of two or more people to establish a business structure, such as a Limited Liability Company ( LLC ) or a Small Business Corporation ( S -Corp), as an alternative to marriage. These enable a throuple, for example, to own property jointly.

Some non-monogamous clients shrink from the “business flavour” of such arrangements, says Ora Prochovnick, a lawyer in San Francisco, whose specialities include contracts and estate planning for non-traditional families. Others find that they spice things up.

Meet Evin, Bunny, Katie and Madeline. Katie (bisexual, she/her) dates Evin (pansexual, he/him) and Bunny (straight, they/them). Evin also dates Madeline (queer, she/her). Neither Evin and Bunny nor Madeline and Katie date, but it’s possible that some of the other people they’ve dated have dated each other. Confused? That’s OK . They sometimes are too, which is why they plan everything.

“At one point, I was literally asking every partner on the same day every week to tell me what days they were available, and which they preferred,” Evin told me. We met last winter at a Christmas bar crawl organised by his local Burning Man group. As a blizzard howled outside, people in Santa outfits passed out home-made toys with playfully demented appendages – a Barbie with a phallic third arm, and stuffed farm animals with several Smurfs emerging out of their sides and rectums.

“I then gave everyone a row in a spreadsheet,” continued Evin, “and each day of the week a column, and coloured the cells in green, yellow and red based on their availability to try to create an optimal schedule wherein I would see each partner the desired number of times.” Evin works as a project manager and took inspiration from work. “It can certainly be seen as a businesslike way to look at things, but the objective is quite the opposite. Scheduling is a significant part of how I try to make sure partners feel respected.”

Planning can be sexy too. Evin and Madeline have a dominant/submissive dynamic in the bedroom, which they extend into everyday life via a productivity app. This pair employ it to reinforce a playful exchange of power whereby Madeline is told by Evin to complete her daily to-do list – taking her psychiatric medication, cleaning her room – in exchange for points and rewards, like a 20-minute back massage or a vacation together. Evin designed the system, but it was Madeline’s idea originally, and she has found it far more helpful than paper planners or other tools she previously tried to help her organise her life. “It makes little everyday things more exciting,” she told me.

Perhaps the most novel technique they employ is a weekly relationship check-in they conceived and dubbed the Six Questions. Every week, Madeline and Evin, and Evin and Katie, enter into Google Docs the answers to six questions about how their relationships have felt in the past week and their goals for the week ahead. Then they discuss their answers, usually over text but sometimes in person.

“What can I do this week to make you feel loved and appreciated?” Evin read from his phone one Sunday afternoon. Then he read his response: “I would like to spend some time aligning on schedules.”

Madeline’s anxieties – question 5 – were around dating other people. “I’ve been trying to get more comfortable doing it,” she said. (One of their protocols is that when Madeline is getting ready for a date, she texts Evin pictures of potential outfits, so he can choose the best one, and implicitly show approval of her choices.)

They reassured each other with tactful familiarity. It was a DIY version of couples therapy by way of a performance review. Before her relationship with Evin, Madeline often felt anxious in unfamiliar situations. On days that were especially frazzling, she sometimes didn’t take her medication, which made things even harder to handle. Running her relationships more procedurally has solved most of those problems. It’s also helped her explore her sexuality; for years, Madeline thought she was straight.

One weekend last winter, Evin came home late at night after meeting a Tinder date. He fed their cat, sorted the kitchen rubbish in the exact manner that Madeline liked it and updated his answers to the Six Questions in the Google Doc. Then he went upstairs, saw “up for kisses” written on the whiteboard on her door and knocked. Everything was in its place and Madeline had never seemed happier.

Jacob and Natasha knew that jealousy was the main obstacle to the success of their open relationship. Jacob believed that the emotion was a residual by-product of human evolution, the animalistic fear that a rival’s genes might supplant one’s own. This fear made less sense in a world furnished with DNA testing, contraception and limitless sexual options an app-swipe away, a world in which people regularly raised children who were not their own and had sex more often for pleasure than procreation. But the tricky thing about emotions was that they didn’t always listen to reason. You could not make sharing people as seamless as sharing rides.

There was one group of thinkers who had the tools Jacob needed: proponents of a new philosophy known to its adherents as rationality. These nerdy internet-users were preoccupied with recognising cognitive bias, applying the lessons of biology and statistics to everything from AI research to fan fiction, and modifying their emotions and desires to achieve their goals. While companies were abuzz with ways to “hack” growth and hiring, rationalists believed that they could hack their own minds – jealousy included.

Rationalists also had a reputation for polyamory. Hannah Blume, a writer in the San Francisco Bay area, wrote an essay about how she hacked herself to “become polyamorous over (admittedly weak) natural monogamous inclinations”. She wanted to modify her “factory settings” and get back together with an ex who had declared himself to be polyamorous. Blume reasoned that if she could convince herself intellectually that polyamory was the right decision, her emotions would inevitably follow. For any doubters who might see the process as evidence of painful self-manipulation on behalf of a partner, Blume declared “I haven’t suffered a hiccup of drama or a twinge of jealousy to speak of.”

When Jacob opened up his relationship, he hadn’t yet discovered the rationalist community, but in many ways, he was already primed for it. He had previously talked himself out of gut reactions with calm, critical thinking, such as when he decided not to cheat on Natasha with his classmate. Surely jealousy would be as easy to circumvent? Jealousy had triggers as well as symptoms. If these were catalogued and avoided, perhaps the monster could be contained.

The first few times that Jacob started feeling jealous about Natasha’s other partners, he distracted himself by playing video games. Eventually he grew accustomed to the feeling, which became less acute as a result. They adopted a “don’t ask, don’t tell” policy that helped them avoid it altogether.

That approach could be used to hack other emotions too, he realised. Whenever Jacob felt himself getting angry with Natasha, he’d search for another angle from which to view the situation. When she failed to keep an appointment he was able to transform his thought from “she doesn’t respect my time” into “she probably got stuck somewhere and feels really bad she’s running late!” If their relationship was going to run the course then conquering such feelings was not just compassionate but pragmatic.

It’s fair to say that Natasha took to the approach less than Jacob. On his birthday, Jacob had plans to see a woman he’d met on Tinder. Afterwards, Natasha was angry. She told him she couldn’t believe that he’d chosen to spend his birthday with someone else. “Why didn’t you tell me ahead of time?” he asked. “You should have known,” she replied.

Less than a year after they moved in together, Natasha broke up with Jacob. He was surprised. Just weeks earlier, the couple had just signed a lease on their apartment for another year. Though Jacob knew they were having problems, he’d thought they were minor: she was working too much; he was absent minded. She had become an exercise fanatic and installed a dancing pole in their apartment. He was gaining weight. And he was also terrible at reading her emotional signals. After all, he’d been doing everything he could to banish anything irksome from his mind.

He responded as only he could: by applying logic to the situation. He set out to get over Natasha by looking harshly at her behaviour, where once he had forced himself to be indulgent towards it. He reminded himself of her flaws. He distracted himself with dating apps. Natasha had flown to the west coast to be with one of the people she had met while they were in an open relationship. Now Natasha and the man were monogamous.

Jacob began to wonder if he had been deceiving himself in his belief that he could transform his own feelings. Maybe he and Natasha weren’t made for each other? At first these thoughts made him despondent. But soon Jacob recognised that he could turn this realisation to practical advantage.

When Natasha came back to New York a month after the break-up, Jacob suggested she move back in. “Your boyfriend is in a different state. I think we could be great roommates.” All they’d have to do was sleep on different sides of the bed without touching. Natasha readily agreed and, for a while, things went well. Soon, she asked if her fiancé could move in with them too.

Jacob saw no pitfalls. “Living in this fantastic apartment and paying one-third of the rent,” he recalls thinking. “They’ve got the bedroom. I move a bed to be just by the window in the living room. Wake up to an amazing view.” Meanwhile, he’d date whomever he wanted.

Jacob still isn’t fully clear about how things went wrong, but he knows this: one evening Natasha’s fiancé stormed out of their bedroom to scold Jacob and a date for laughing (it was rude to laugh when someone else is in a bad mood, the fiancé said). Soon after, he confronted Jacob about using his kitchen knife. Jacob made a joke that was misinterpreted as a threat and Natasha’s fiancé was about to call the cops before Natasha managed to calm things down. Soon after, Natasha and her fiancé moved out. A month after that, they broke off their engagement.

Natasha no longer speaks to Jacob. This makes him sad and confused. Jacob takes a sip of tea as he recalls the most recent email from her: a request that he take down or untag photos on Facebook of them together in some of their happiest moments, on a trip to Israel and at a flash mob in New York. She’s monogamous now, he thinks, and wants to leave him and that period of her life behind.

Jacob doesn’t blame rationality for what happened. If he had understood its principles earlier on, it would have saved them strife, he told me. In fact, Jacob now believes he fell victim to cognitive bias, a cardinal sin of rationality, by assuming that other people thought in the same way that he did. “I don’t think it ever crossed my mind that overriding my emotions and convincing myself that Natasha and I were perfect for each other could be bad for me,” he said.

At one point, before their breakup, Jacob suggested that Natasha try his approach to emotional control. She replied, “it’s impossible.” She thought emotions could be repressed but never reconfigured. Moreover, feelings in the raw – messy, overpowering, often stubborn – were actually useful guides for making choices in love. Natasha was incredulous that romance could ever be hacked by Jacob or anyone else.

On a recent evening in Brooklyn I met Stephanie, a biologist in the final year of her P h D . She is the woman that Jacob’s Goddess Spreadsheet advised him to marry. Stephanie is pale and classically beautiful. Though initially shy, she opens up over time. She speaks in careful, grammatically complete sentences while her fingers flick each other under the table. I saw why she would have an advantage in a schema that forces its deviser to extrapolate swathes of personality from a limited set of conversations.

According to Jacob’s spreadsheet, Stephanie attained high marks in “Can talk at my level about science, rationality, big issues” and “Openness” (Stephanie had discovered non-monogamy during a prior long-distance relationship). She was also darkly funny. When Jacob and Stephanie were matched on OK Cupid, she explained the day-to-day of her research on fruit flies: “[I] rip their butts off, squeeze the fat off like a tube of toothpaste, and turn them inside out like a sock.”

Still, the final spreadsheet results surprised Jacob. He’d expected a woman with whom he had more immediate chemistry to get the top score. Jacob was also an unexpected choice for Stephanie. Typically, the men she falls hard for are more sensitive. “If I was entirely following my heart, I probably wouldn’t be with him,” she told me.

A sign that they had made the right choice came when Jacob told Stephanie about the spreadsheet. She smiled and asked a question about his algorithm design. Stephanie and Jacob got married in 2017. Their relationship has always been open, save for a few months at the very beginning and, more recently, a stretch during which they worked on their bond.

Stephanie isn’t a rationalist, and she understands the backlash against Jacob’s methodology: “‘Oh, like this guy is such a catch, chooses a girl with a spreadsheet’,” she quips. “But I felt like everyone sort of does something like that…what are the pros and cons to being with this person?”

Her reaction confirmed a theory of mine: spreadsheets and other corporate analyses of sentiment function in much the same way as older tools – personality quizzes on OK Cupid, psychoanalysis, even astrology. All these systems provide structure to the murky depths of our feelings. They may seem arbitrary but they help to make our contradictory and fluctuating desires comprehensible and communicable.

Today, Jacob tries to remain aware of which of his emotions contain useful information. They’re another data point to consider. “If all you care about is forming true beliefs about the world, listening to and understanding your emotions is a big part of it, because all you have is your brain. And a big chunk of what your brain does is make you feel stuff.”

“Love is still mysterious. Sex is mysterious,” he concluded. “I’m just trying to shine a small light in the darkness.”■