Kristen Roupenian’s short story Cat Person was published by the New Yorker in December 2017 and, to the author’s best recollection, it went up online on a Monday. The 37-year-old was living in Ann Arbor, Michigan, while completing a fellowship in writing, and for three or four days after the story came out, enjoyed the world’s customary reaction to most fiction, and all short stories – complete indifference – while basking in the achievement of it having been published at all. “I was thinking, ‘Wow: that was the greatest thing to ever happen, and now it’s over.’” She smiles. “Then it was Friday.”

By the standards of true global celebrity, there is only so far a piece of fiction can go; as David Foster Wallace used to say, the most famous writer in the world is about as famous as a local TV weatherman. Still, what happened with Cat Person remains singular to the extent that, for what seemed like the first time in publishing history, it slammed together two alien worlds, social media and serious fiction, in a way that stretched the boundaries of literary fame.

The story of Margot, 20, and Robert, 34, and their disastrous short-lived relationship was written a few months before the #MeToo movement took off, and by the time it came out its themes – the power imbalance between older men and younger women; the dynamics of coercion; the hideous chess game of early courtship, with its currents of self-delusion and bad, bad sex – chimed with what felt like the only conversation in town. In the weeks after Cat Person was published, it was shared millions of times, inspired spoof Twitter accounts and, after being widely mistaken for memoir, was prosecuted as part of a man-hating liberal agenda. The author, meanwhile, sat in a coffee shop in Ann Arbor, where she remained largely oblivious to the fuss. It was Callie, her girlfriend, a fellow student who is better plugged in online than Roupenian, who looked up from her laptop and said, “Something’s going on with your story.”

A year later, we are in the slightly ramshackle house the two women share in southern Michigan, and everything about Roupenian’s life has changed. She is still adjusting to the shock of such widespread attention – Cat Person went on to get more than 4.5m hits and become the most-read piece of online fiction the New Yorker has published – something about which, she says, “I can’t think without feeling shrunken. It’s like everyone’s talking about me, and it makes me feel small.” Roupenian is slight and soft-spoken, her rapid speech underscored with a kind of urgent levity that makes even her most critical assessments sound basically amused.

For a hot second, Roupenian seemed like the world’s number one authority on heterosexual dating dynamics

There are practical differences to her life these days, too: most notably, after two decades of being a student (before her master’s at the University of Michigan, Roupenian spent seven years on the PhD programme at Harvard) having more than one option at her disposal. Roupenian finished her fellowship last year and is waiting for Callie, a year behind her on the same programme, to catch up, after which they may move. “It’s an extraordinary luxury to just take a breath – the tenuous year-to-year, two- or three-year existence is so ingrained in me that I almost can’t imagine thinking, ‘Just pick a city and move!’ I’m still wrapping my head around it.”

There have been other adjustments. For a hot second, Roupenian seemed like the world’s number one authority on heterosexual dating dynamics, and the news that she is now living with a woman was considered sufficiently thrilling to make the front page of the Sunday Times last year, much to Roupenian’s horror. “The private New Englander in me – ” she pulls a face. “There’s stuff about you that’s being interpreted and that feels weird. And yet, when they did it, my sense that I have to manage how other people know about [my relationship] was suddenly out of my hands. You can Google me and know my life now! And it’s actually fine.” She goes deadpan for a moment. “Woo. Fine.”

The biggest change to Roupenian’s life has been financial. Cat Person appears as one of 12 short stories in You Know You Want This, a forthcoming collection that won Roupenian a reported $1.2m advance and is being adapted into an HBO series. The stories are mostly a triumph: savage, grotesque, often very funny, mostly to do with the inability of one person ever truly to know another, and the moves one makes to cover this up. After reading them in one gulp, it is hard not to conclude that everything is terrible and everyone is awful, and yet there is a weird kind of optimism in the fact that most of Roupenian’s characters are at least 30% asshole; we are none of us unimplicated.

In The Good Guy, far and away the best story, an amiable man named Ted, turned bitter by female rejection – this is a common theme of Roupenian’s; the extent to which men rejected by women hate women, and women rejected by men hate themselves – sits with a girlfriend he despises and thinks, “It was almost existentially unsettling, that two people in such close physical proximity could be experiencing the same moment so differently.” In The Mirror, The Bucket, And The Old Thigh Bone, a story that seems to have sprung fresh from the 14th century, the heroine considers the possibility that “the person she was in love with didn’t exist, except in her own mind”. One of the pleasures of reading Roupenian is her drive-by assassinations – “Ellie worked in communications, which meant that she spent 90% of her time crafting emails that no one ever read” – while the big thematic plates of vanity, hubris, self-delusion, slide by underneath. “The world was pitiless,” observes Ted, with weary nihilism. “Nobody had any power over anyone else.”

The question of power is at the heart of every story and it’s something about which, Roupenian believes, one’s understanding changes with age. Cat Person was inspired by a few dates she went on in her mid-30s, in a short period between the end of her relationship with a man to whom she was engaged, and meeting Callie. She hadn’t dated since her early 20s and what struck her about that experience, she says, “was how messy it was. And one of the things I thought was that at 36, I have a handle on power dynamics and gender and all of this stuff. And it just seemed to me that at 20 – which is an adult, officially, at which age it is acceptable to go on a date with someone in their mid-30s – how could you possibly engage? It seems to me, now, so young.” One of the reasons Roupenian wanted to write the story was to explore how hard it is to delineate what is going on when attraction and repulsion combine, and when – as one tends to at 20 – one is lying to oneself about being in control. In such a case, she says, “the complications of it are more subtle than just, ‘Here’s this jerk who’s hitting on me.’”

At that age, says Roupenian, bad dating experiences made her feel “so alone in my head that I couldn’t articulate it”. After her story went viral, she couldn’t help thinking that “everything would’ve been different for me when I was at the age of Margot if I’d understood how collective some of these experiences are”. Certainly when she was in her teens, she says, she would have benefited from the conversation around feminism being more nuanced than “everybody shouting ‘Girl power’ and ‘Girls can do anything!’ Which was great, but also, a lie.” She shrugs. “Who can say what it’ll be like for babies born today, in 2040? But I have to think that knowing other people are thinking your strange, ugly thoughts is a good and comforting thing.”

***

One of the questions Roupenian asks repeatedly in her fiction is to what extent one can ever clearly see the person to whom one is attracted. It’s a tendency among women to interpret their partners in a way that, Roupenian realised recently, is deeply gendered and completely unhelpful. “Often in relationships between men and women, there is this weird pact that it’s the women’s job to interpret their relationship for the men. That they have a right to say, ‘The problem with you is that you’re afraid of commitment, and if only you would show up at my house at an approximately reasonable time then we would be fine.’ And that is bullshit: that the men are ready to outsource their own understanding of themselves to the women, and that the women will do that job so the men will do what they want. And yet it’s a sort of agreed-upon game.”

Has the dynamic been different in her current relationship? “I do think [that dynamic] can be true of two women, and maybe of two men, but I feel like the relationship that Callie and I have is one in which we recognise it’s not either person’s job to explain the other person – and that that’s actually a power grab. I think we all grab for different kinds of power, and maybe as writers you come to the world thinking, ‘I understand why people act the way they do, and that ought to give me a certain amount of power.’ But the fact is, people do what they want to do. There’s always a moment, whenever you’re having a fight, when you think, ‘Oh, I’ve solved it!’ And the other person is like, ‘Well, congratulations to you, I will continue to live my own life. Please back off.’”

Kristen Roupenian: “My whole life became a trending hashtag.” Photograph: Chuk Nowak/The Guardian

It is these sorts of observations, and the sexual frankness of some of the stories, that have made Roupenian’s work uncomfortable reading for some of the men in her family. Roupenian – her father is of Armenian heritage – grew up outside Boston, where her mother, a retired nurse, and her sister remain. (Her father, from whom her mother is divorced, is in Alaska with her brother.) It’s not that her dad, a doctor, isn’t supportive, she says. “But there’s such a split in my family where the women are reading the stories and loving them and we have just decided, with some of the men, that we’re not going to talk about it.” She bursts out laughing. “The book is dedicated to my mum, and when Cat Person got published I had to read it aloud for the podcast. We were all waiting for my sister’s baby to be born, so I was like, ‘Ma, I have to practise’. And I read this rabid sex scene aloud to my mum and she was just so cool with it. She has only ever been wildly supportive of my writing and seems to get it, viscerally.”

***

In high school, Roupenian worked on the literary magazine, but although she knew she was good at writing, she didn’t have any particular longing to become a writer. “At that stage it felt like work,” she says. “There was some sense of obligation that was deadening. When I went to college, I felt so happy to do something new.” She studied first at Barnard, in New York, where her academic interests were health and psychology. For a while, she thought she might have a career in non-profits and, at the age of 21, went into the Peace Corps, spending a year volunteering in Kenya. It was after returning to Boston and getting an interim job as a nanny that she decided to turn her experiences in Kenya into a novel. “But the truth is, you can’t write about something if you don’t understand it. I realise now that I was exhausted, because I was being a nanny for 50 hours a week, and so I had writer’s block and couldn’t come up with anything. It became this miserable endeavour that I set aside, to go to grad school for English. I thought, ‘Oh, if I can’t write books, I’ll write about them.’”

In the end, while doing her PhD at Harvard, she ended up writing a “sort of thriller” set in Kenya, which she wrote quickly and found very satisfying, drawing on “the tools of tension and dread and revulsion” she had loved reading in Stephen King as a child. The novel didn’t sell to any publisher – “rightly, I think”. But for the first time, she says, “I thought, I believe I’m close enough to do this. I have to go for it.”

The dynamics of thriller and horror writing were among Roupenian’s first loves as a reader. She is superb at creating a supernatural atmosphere that, like the best horror writing, seems rooted in the creepiest aspects of the material world. In the story Scarred, a woman finds an old book of spells, magics up a vulnerable man, and proceeds to destroy him via a thousand small cuts. In Death Wish, a woman asks a man to hit her during sex, and he demurs while wondering, “Can I punch her? Not as hard as I can, but just kind of… symbolically?”

The emails flooded in, friends from the deep past, creepy messages about sexual encounters, offers from media outlets

Does she really believe no one has power over anyone else? “Emotionally, I do believe that’s true. But I think it requires a lifetime of learning to recognise the patterns.” For Roupenian, it has been a case of recognising a tendency to overestimate the extent to which “someone else has control over my happiness and ability to move in the world”, and, by extension, her control over others: “That if you’re unhappy it’s my fault, and my job to fix it. I do have a responsibility to make other people happy – you have to be a good person. But that is contradicted by the thing I have felt increasingly as I get older, which is that I do not have the power to make you happy; my ability to fix you is so limited; and my desire to fix you is complicated. For me, the process of getting older and seeing things more truly has been realising how little power we have over each other.”

This is, to some extent, a very freeing realisation, although there’s a risk of becoming detached. One has to remain somewhat vulnerable, surely? “You can be vulnerable, it’s true – it’s an endless negotiation, and in relationships that have been difficult for me, feeling like loving someone meant trying to save them. For a long time I thought that was a critical part of loving someone, in a way that I do think codes female. It seems deeply embedded in ideas of what it means to be a good woman. Of helping people fix themselves; changing them a little, seeing the subtle violence and reaching for control.”

Roupenian does not think that now; in fact, these impulses strike her as downright unhealthy. Her self-protective instincts have been sharpened by the experience of Cat Person going viral. As the emails started flooding in, she grew truly alarmed. (These ranged from the re-emergence of friends from the deep past, to creepy emails from men describing their sexual encounters, to offers from media outlets around the globe to come on their shows and explain herself.)

“There is so much thoughtful, smart conversation around the story, but – and this is inherent to conversations on the internet – it is entwined with such vitriol and visceral emotion. I just have to let it be something separate that happened to the story, and happened to me, and that I can’t control. It is not my conversation. It’s too strange and disorienting.”

The oddest thing about the whole experience, she says, was how it seemed simultaneously huge and, like everything else on the internet, deeply transient and trivial. “You saw both everybody suddenly giving a shit, but also not at all – it was just a trending hashtag, a piece of entertainment. That was my whole life! That’s what’s so weird about how it makes you feel wrong‑sized. You’re only ever going to be a flash in other people’s brain pans, and it’s weird to see that reflected back at yourself.”

One of the funniest outcomes has been the extent to which, in book events and other public appearances, Roupenian has come to be regarded as a kind of relationship guru, something that makes her laugh, given how screwed up every single character in her book is. “It’s funny to imagine people reading the stories and thinking: ‘I should take advice from her!’” What people are responding to, in fact, is a generosity in the writing; a fundamental understanding that good, or good-ish people, can still end up causing enormous pain, powered by self-loathing and a commitment to an unworkable persona. Margot doesn’t want to sleep with Robert, but feels it’s too late to back out; Ted doesn’t want to date Rachel, but it seems absurd to break up with her out of the blue. (“If he tried to break up with Rachel right now, while she was halfway through a breadstick, surely the first thing she’d say would be, ‘If you knew you were going to break up with me, why did you literally just agree to go with me to visit my cousin on Sunday?’ and he would have no answer.”)

No one is on trial in these stories, she says. “In terms of what I’m interested in, I write a character from a place of disconcerted surprise at their own behaviour – of people who can’t quite navigate where they are. Those feelings of ‘I don’t understand how I got here’, or ‘I came here with good intentions, and now I’m causing harm’ – they cross gender boundaries, and probably all boundaries.”

In the end, it comes down to storytelling, she says. Looking back at her dating life, she is amazed at the times when “I have spun out in relationships where later I was like, you knew that person for a week. To me, part of the anxiety that can come in romantic relationships is, ‘I have a story that is unravelling.’ That can be really hard. It’s caught up in ego, and power, and control. Which is separate from ‘Maybe this person likes me, maybe they don’t.’”

It is a great relief to be on the other side of all that, says Roupenian, and to have a tiny grain of perspective. It may be that, as per her stories, everything is terrible and everyone is awful, but the wisdom of one’s late 30s is also a wonderful thing. “I read something recently that said very straightforwardly that flirting is a management of information. As soon as you know for sure what’s going on, the flirting stage is over. The flirting is ‘I’m not sure yet.” She grins. “Put that way, I thought, ‘Oh: maybe it’s not that bad.’”

• You Know You Want This by Kristen Roupenian is published on 7 February by Jonathan Cape at £12.99. To order a copy for £8.99, go to guardianbookshop.com or call 0330 333 6846. Roupenian is in conversation with Hadley Freeman at a Guardian Live event in London on 7 February

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