The first condition was to tell each other who they were dating. The second was to share when they were dating someone else. And the third—the most sacrosanct—was that no date would cross the threshold into their shared home. Despite these stringent outlines, it took just a couple of months into their relationship for Bailey*, 23, to discover that his partner, Morgan*, had broken every single one.

Even though, by its very nature, an open relationship signifies a significant degree of liberty, Morgan admitted to intentionally disregarding boundaries “so they could feel like they had more freedom to do what they wanted.” Though the couple remains together—now in a monogamous relationship—the experience soured Bailey’s opinion on non-monogamy. “I’ve come to believe that non-monogamy attracts avoidant personalities, the relationships are rife with jealousy, and there’s a lot of dishonesty,” asserts Bailey. “It’s far too easy to use the idea of non-monogamy as a cover for what is actually cheating.”

In recent years, ethical non-monogamy (ENM) has become the topic du jour in culture, online discourse, and, of course, in dating, with once-fringe apps—such as Feeld, which caters to non-traditional relationships—now considered mainstream. According to 2026 Tinder data shared exclusively with Cosmopolitan UK, 27% of UK singles aged 18 to 25 say they’ve considered ENM, while a further 34% haven’t considered it but say they’re open to learning more.

And yet, non-monogamy still appears to be widely misunderstood—and sometimes, it seems, purposefully so. Anecdotally, more people like Bailey are reporting run-ins with daters who weaponise ENM, using it as a get-out-of-jail-free card for bad behaviour. This was most famously exemplified last year via Lily Allen’s explosive divorce album, West End Girl, based on Allen’s account of her open marriage to Stranger Things’ David Harbour—which she claims was marred by relentless cheating and lies. It was exemplified again in April by Megan Thee Stallion’s accusations that her now-ex Klay Thompson cheated and then expressed misgivings about monogamy. And in March, by the viral controversy surrounding Lindy West’s polyamorous arrangement with her husband.

In the midst of all this, a more vocal backlash to non-monogamy has been growing, notably among young people, who’ve typically been more open to non-traditional relationship structures than older generations. On Reddit, scores of people in their late teens, 20s and 30s are sharing ENM horror stories in the r/monogamy subreddit, while others look for reassurance about their anti-ENM perspective in the r/GenZ subreddit, with some even declaring themselves ‘polyphobic’ (itself a controversial term, as some reject the suggestion that criticism of non-monogamy is bigotry akin to homophobia, asserting instead that it’s a lifestyle choice rather than an identity).

So, after years of booming popularity, are we entering a new era of anti-non-monogamy? And, is this proof that the non-monogamy ‘experiment’ has failed, or does it tell us something deeper about how we approach relationships in the first place?

Three’s a crowd

Master communicator, boundaries professional, conflict resolution expert, and skilled timekeeper. If non-monogamy had a job description, these would be the required skills. Some people are cut out for it, others aren’t. It may work for you in one relationship, but not in another. It will probably bring up emotions that you don’t expect and that you might not know how to handle. In short: it’s no walk in the park, explains relationship therapist Catherine Topham Sly. This might be why, despite being prevalent in conversation, non-monogamy is still less common in action. As per 2026 YouGov data, just 4% of Brits have been in open relationships and 2% in polyamorous ones.

“Even in non-monogamy, we still need to feel chosen in some meaningful way — valued, prioritised, and emotionally safe,” says Topham Sly. “Exclusivity can offer an in-built sense of security. When that isn’t part of the structure, consistency, reliability, and trust become even more important.”

Topham Sly explains that key personality traits of those who find happiness in ENM are “a strong sense of self and an ability to tolerate insecurity, as well as moments of comparison”. Non-monogamy is best entered into when one has reached a sense of balance in their life, so that, she says, “your sense of identity, fulfilment, and self-worth aren’t tied to your partner, and they aren’t your only source of emotional support”. When these elements aren’t present? That’s when things go wrong.

In 2024, 28-year-old Bea* came out of a decade-long relationship, eight years of which were non-monogamous. Having got together when they were 16, at the age of 19, Bea’s then-partner, Niamh*, asked if they could be polyamorous. It was good for a while: Bea never found it hard to get dates and have one-night stands. But things soon started to unravel. “I realised that I was using sexual validation as a way to avoid dealing with my low self-esteem,” she says. “The fact that I had a lot of sex was proof to me that I must be worth something. In truth, I had never felt lonelier. I think on some level, I continued because I unconsciously wanted one of these flings to fall in love with me and save me from my decaying relationship.”

In hindsight, Bea can see that things weren’t great in the relationship, and that opening things up may have been Niamh’s way of “taking some of the pressure off” a “co-dependent” situation. But when Bea became chronically ill, Niamh wasn’t there for her—she was too busy dating while Bea was at home sick. Instead of supporting her, the couple’s poly friends commended Niamh for ‘living her truth’ during a time of stress.

“There’s definitely a culture in the community where people are made to feel like they can’t even expect the bare minimum [from their partners],” says Bea. “Being housebound in my 20s and having my girlfriend tell me to practise compassion, want less of her, and prioritise her happiness felt like the biggest ‘fuck you’.”

This seems to be a common complaint among many formerly non-monogamous people. Some told Cosmopolitan UK stories of partners neglecting them once they had, as one 33-year-old woman put it, “shiny new toys to play with”; others talked about being gaslit, including a 37-year-old woman, who says her feelings were regularly dismissed by poly friends who told her to move past “suspicion and fear”, before she eventually discovered her primary partner was lying and sneaking around.

In these instances, the communication and empathy that’s meant to define ENM appears to have been thrown out of the window in favour of secrecy, selfishness, and a pressure to repress feelings. “It’s the enshittification of relationships. The idea that you should fuck more people and want less from them,” says Bea. “It’s hook-up culture cloaked in therapy speak. There’s a lot of pressure on people, especially women in monogamous relationships, to erase their boundaries to make their partner happy.”

Community guidelines

Therein lies the key to non-monogamy: if both partners don’t enter the arrangement willingly, even with equal enthusiasm, it’s likely not going to work. And yet, many feel they should embrace the opportunity if it arises, either to appease their partners or wider communities. In LGBTQ+ circles especially, monogamy can be viewed as a patriarchal ideal, one that preaches marriage, picket fences, and 2.4 kids. Queer culture’s historical rejection by the status quo makes a conventional relationship with monogrammed pillowcases extremely unappealing. But, says Bailey, the flip side is that it “paints those who engage with monogamy as lesser-than, uneducated, or complicit—and that can easily sway someone into feeling guilty for their own dating preferences”.

For many, whether they’re LGBTQ+ or not, this pressure to buck convention is incongruous with what they’re craving. In fact, Bumble’s 2025 Dating Report shows that the majority of women (59%) are increasingly yearning for stability, safety, and emotional security in their romantic lives. And while non-monogamy can, of course, provide all these things, it’s not always as straightforward. “The liberation non-monogamy offers to some can feel outweighed by the emotional risk it involves,” says Topham Sly. “There’s a strong cultural narrative that non-monogamy is inherently more evolved or progressive, but many who try it discover that the very human challenges of jealousy and attachment insecurity persist. In a world that feels overwhelming, the backlash might reflect a craving for simplicity and emotional safety.”

In the UK, monogamy—a social construct upheld by Christianity—remains the norm. And, amid a cultural shift towards conservatism and the return of ‘traditional values’ (which may be partly to blame for the non-monogamy backlash), there is more pressure to be exclusive than polyamorous. What’s more, it’s still significantly more taboo to date multiple people at once; so much so that many keep their ENM relationships a secret for fear of judgement. Non-monogamy, then, has long been stigmatised in small-c conservative circles, and yet this negativity appears to be seeping into more people’s understanding of it. As per Tinder’s data, ‘complex’ (28%) and ‘messy’ (26%) were the qualities most associated with ENM among 18 to 25-year-old UK singles. The same data shows that the most common things young people have heard about ENM are that it’s a form of cheating (18%) and that couples only pursue it because they’re bored or unhappy within their relationship (17%).

But for many couples, it does work—and far better than any attempts at monogamy have served them in the past. Leanne Yau, a polyamory educator known as Poly Philia, who’s been non-monogamous for 10 years, credits her relationship structure with giving her “flexibility and freedom, independence to explore [her] own desires, and emotional awareness.” Yau believes the backlash largely stems from “the internet loving to sensationalize everything”. “I think non-monogamous people are being scapegoated for a lot of dating frustrations,” something she believes “contributes to an existing narrative that polyamorous people are irresponsible cheaters who can’t control themselves and will take advantage of you, which is not the case.” For Yau, being non-monogamous “makes [her] a better person and partner.”

For Bea, it’s a case of start as you mean to go on. “A lot of the messiness between the pro- and anti-crowd comes from people using non-monogamy to soft-launch a break-up, or to not lose access to their emotional safety blanket while they fuck hotter people,” she says, advising: “Don’t get into a monogamous relationship and ask to open it up; likewise, don’t ask a poly person for exclusivity.”

There’s no doubt that some people are abusing the idea of non-monogamy—and its cultural cachet in certain circles—to get away with bad behavior. There’s also likely a lack of individual research into and understanding of non-monogamy, particularly among younger people who are experimenting in fledgling relationships, which can see them enter into agreements without being fully prepared for the reality of them. Of course, similar flaws and abuses exist in monogamous relationships, too. There’s no clear-cut way to avoid bad feelings and manipulation; we all have a responsibility to treat one another well and with respect. If someone is determined not to do that, they’ll find a way no matter the relationship structure.

*Names have been changed

From: Cosmopolitan UK