Do open relationships last?

The honest answer is that nobody can tell you whether your relationship will last, and the research is thinner than the confident claims on either side suggest. The two studies cited below have different limits: one compares satisfaction rather than survival, and the other follows a single, specific group for twelve months. Treat “open relationships always fail” and “open relationships are just as stable” as beliefs looking for evidence, not findings.

What the research can compare is satisfaction. A meta-analysis of 35 studies and 24,489 people found that consensually non-monogamous and monogamous respondents reported equivalent relationship and sexual satisfaction, with no difference by agreement type and no evidence of publication bias (Anderson et al., Journal of Sex Research, 2025). Its authors also set out the field’s methodological challenges and call for more research — and satisfaction reported at one point in time is not the same thing as durability.

The only study cited here that measured break-up is a one-year cohort of 338 young sexual and gender minority people assigned male at birth, whose mean age was about 21 and many of whom were in relationships less than a year old. Its non-monogamous group was 49 people — 41 with a restricted-non-monogamy agreement merged with 8 who reported an open agreement, after the authors found no differences between the two. Across all groups, break-up ran 48.6% to 58.3% at six months and 63.5% to 67.5% at twelve months, and the differences between agreement types were not statistically significant. Participants with a monogamous agreement did start out reporting higher satisfaction and commitment than non-monogamous participants, and the authors report that having a monogamous agreement was indirectly associated with lower break-up through commitment. Their own summary is that people with non-monogamous agreements look “fairly similar” on average but are “somewhat less satisfied and less committed”, that the results were mixed, and that the findings offer some preliminary support for a monogamous agreement as a protective factor against break-up. They also report low power (0.32 to 0.40) to detect even a small difference, and note that the baseline satisfaction and commitment differences are cross-sectional and so cannot speak to direction of effects (Godfrey, Whitton, Dyar, Newcomb & Mustanski, Archives of Sexual Behavior, 2021).

Beyond the studies, what people commonly suggest is unglamorous. Watch for the ordinary failure modes — mismatch, avoidance, time, unspoken resentment — and for two more: an agreement that no longer matches what someone wants, because someone said yes years ago and circumstances changed without anyone saying so out loud, and rules nobody revisits, which quietly turn into secrecy. The practices commonly recommended are explicit agreement, honesty about what each person actually wants now, regular check-ins, a working way to talk about jealousy, safer-sex promises that are kept, and treating closing the relationship as a legitimate option rather than a failure. This is general relationship advice, not a finding from the research above.

If you are deciding whether to open a relationship, treat it as a series of decisions rather than one. Start with the conversation, agree on limits you can both actually keep, revisit them after anything new happens, and keep the relationship you already have — time, attention, affection, logistics — visibly funded. The answers on open relationships, open marriage and handling jealousy cover the mechanics; this one is about the odds, and no study can predict yours.