An Indian man recently asked a question on Quora that got to the heart of a perpetual source of conflict among many married couples the world over. His fiancee makes less than a quarter of his salary, he said, but she doesn’t intend to quit her job when they get married.

“She expects me to help her in household chores,” he wrote. “I frankly told her that please marry a guy who earns 4.5 Lpa [the same salary as her], he will do whatever you demand, did I say anything wrong?”

Condemnation came fast and hard. An Italian man offered another hypothetical in answer:

If I work two hours a day as a freelance consultant for 2000 euros an hour and my wife earns 1000 euros a month working 12 hour shifts should she do the household chores because she’s POOR?

Beyond the original questioner’s crass financial analysis and blatant sexism, the issue he raises is a plague on many relationships with income gaps: How to divide up housework, especially when one person works more hours, makes more money, and has more outside demands on their time, while the other has more responsibilities in the home.

Even before Nobel Prize winner Gary Becker decided to analyze marriage as a market made up of scarce resources, couples have faced balancing formal employment (working for money) and managing a family and home (working for no money).

Should the partner with the less-demanding job leave every day to get the kids from day care, or will that actually hamper that person’s future career prospects, and perpetuate the imbalance in household responsibilities? Who stays home when a kid is sick, manages homework and bedtime, and cooks the endless meals children require? Is it always the one who earns less? If one person chooses to stay home full-time, or work part-time, while the other works full-time, should the (endless, dull) work of the home default to the stay-at-home, income-less, or part-time partner? That might seem logical, or it might seem wildly unfair.

Ultimately, every couple has their own definition of what makes a partnership fair and equal. It’s a negotiation that should start with the premise that everyone pitches in, and everyone makes compromises.

Economics can help

Economics is all about the allocation of scarce resources, and finding smart ways to allocate your own scarce resources, like the hours in your day, the money in your bank, your sex drive, your patience, and the willpower to pick up yet another pair of dirty socks from the living room floor without losing your mind.

That does not mean couples should expect to split everything 50/50. As I argue in the book I co-wrote, It’s Not You, It’s the Dishes, 50/50 splits often results in constant renegotiation and endless bickering.

A better model is that of specialization, brought to us first by Adam Smith in his 1776 bestseller, An Inquiry into the Nature and Causes of the Wealth of Nations. In it, he showed that the secret to a nation’s wealth was not money but labor, and specifically, labor specialization. Four decades later, David Ricardo, a Brit, explained how to specialize: Not by doing everything you do well, but by focusing on those things you do better relative to others (the theory of comparative advantage).

If I pay the bills and my husband does the yard work, I will strive to make bill-paying more efficient as I go, setting up systems and ways of keeping track. Likewise, My husband will get better at yard work and do it in less time. Knowing our respective roles means no negotiating; just executing. Through the miracle of simple math, doing things this way literally frees up hours.

You can of course change specializations over time, and you can make someone who is not a specialist in something, say toilet cleaning, a specialist very easily. The key is transparently establishing who does what and then changing it when it needs to be changed.

Fairness matters

It is key that whatever deal that is struck feels fair to both parties.

Consider the ultimatum game, often played in economics research. In it, one player is given cash, say $20, and has to decide how much to give away to player two. Player two can reject her offer, which will leave both of them with nothing, so player one wants to give away just enough that she keeps as much of the stash as she can, but doesn’t risk offending her partner so much that she loses everything. Classical economics would predict that player one gives very little: if she offers $1, that’s one more dollar than player two had before the game started. But in reality, player one tends to give away 40-50% of the money, and player two tends to reject the deal if less than 30% of the total amount is offered. Fairness matters.

It is because we value fairness that it is patently unfair to expect your wife to do all the housework, regardless of what you earn. Endless housework can feel more grueling than a job outside the home, especially when it also involves taking care of kids. Everyone needs a break and a change of scenery. Also, kids and couples benefit when both parents stay involved at home.

Back in 1990, Pew asked couples what made a marriage work, and fewer than half (47%) of adults said sharing household chores was very important. When couples were asked again 17 years since later, no other item on the list (which included faithfulness and happy sexual relationships) had risen in importance nearly as much, and across the demographic landscape―among men as well as women, marrieds as well as singles; old as well as young.

Saying you want equality in your marriage is one thing, ensuring it is another matter entirely. Regardless of what most couples aim for, this is what the split still looks like today, according to another Pew study, from 2015:

Research shows that sharing housework pays: Couples who are happier and stay together generally share housework (the cause and effect here is unclear), and may even have more sex. Common sense also feeds in: As Carol Channing famously said in Free to Be You and Me, “Your mommy hates housework, your daddy hates housework, and I hate housework too. And when you grow up, so will you.” Her solution? “Do it together.”

Of course, no one said finding harmony is easy. Myra Stober, a labor economist and noted feminist recently told Stanford graduates that family and work are “both greedy institutions” but that it’s possible to balance two careers and a family. “You can harmonize two careers with a successful family life, including children, if you want them. But it is a decidedly complicated goal, and our society doesn’t help.”

Economics offers insights, especially behavioral economics, which examines our irrational tendencies. But of course, marriage is more emotion than contract. To our Quora man’s question, another man gently pointed some key differences between having a life partner and say, forming an LLC:

I think you should understand the basic difference between an emotional relationship and a business transaction. Your assumptions and views are directly derived from a transaction point of view. If you are about to invest in a venture and the capital ratio is approx 4 : 1, then your demands are viable and legit. your business partner should compensate the deficit by contributing more man-hour to that. But, marriage or any human relationship is not a financial investment, rather it’s an emotional one. I would suggest you to re create the balance sheet, this time taking the emotional capital into account.

I agree. Once you figure those things out, you can contemplate what division of labor might contribute to your happily-ever-after. Or, you can use your extra money to hire a cleaner.