
Open Relationship
Open Marriage · Sexually Open Relationship · Non-Exclusive Relationship
Added 26 Jul 2026 · Updated 22 Aug 2026
A committed couple who, by explicit and ongoing mutual consent, allow one or both partners sexual involvement with people outside the relationship. The couple itself stays the primary, central bond.
- Prevalence
- Common · 4% of adults
- Type
- Relationship structure
- Family
- Open structures
- Also known as
- Open Marriage, Sexually Open Relationship, Non-Exclusive Relationship
- Confidence
- Medium confidence
- Reference
- Wikidata Q1481481
Overview
An open relationship is a committed romantic partnership, most often between two people, in which the partners agree (explicitly and on a continuing basis) to allow sexual and sometimes limited romantic involvement with people outside the relationship. The couple remains the primary unit: partners typically share a home, finances and a joint social identity as a couple, and outside involvement is added around that core rather than replacing it. That structure is what separates an open relationship from polyamory, where a person may build several romantic relationships that all carry serious weight with no single "main" partnership, and from swinging, which is usually organized around a couple's joint, often simultaneous participation in sexual activity with other couples at a shared event rather than each partner separately pursuing outside relationships of their own.
Examples
An open relationship is defined by a couple staying central while sex is permitted outside it, which makes the neighbouring structures the fastest way to fix its boundaries.
What the term covers. A married couple who agree either may see other people sexually, with safer-sex practices and a disclosure habit settled in advance; a partnership with an explicit rulebook (a vetting step, no repeat partners, no one from the shared social circle) and one that agrees only on broad limits and decides case by case; and arrangements where limited romantic warmth toward an outside partner is tolerated, provided the couple remains the centre. "Open marriage" is the same arrangement inside a marriage.
What the term does not cover. Polyamory allows several full romantic relationships with no single main partnership; swinging is couple-centred and usually joint, often at organised events, rather than each partner separately; monogamish couples permit rare named exceptions instead of a standing allowance; don't ask, don't tell is an open relationship with the disclosure step removed. Infidelity is not a version of it: agreement is the whole definition.
How the word is used. "Open marriage" arrived in 1960s sociology meaning a marriage freely chosen rather than arranged, and was popularised by Nena and George O'Neill's 1972 bestseller, whose argument was about personal growth; press coverage of a single chapter narrowed the phrase to sexual non-exclusivity within a decade, a shift the authors regretted. "Open relationship" is the later, marriage-neutral form, and is the term surveys use.
History
The underlying idea is older than the vocabulary. "Open marriage" entered sociological writing in the 1960s as the counterpart to "closed marriage," describing a union chosen freely rather than arranged by family or custom. Nena and George O'Neill's 1972 book Open Marriage: A New Life Style for Couples took the phrase mainstream, spending forty weeks on the New York Times bestseller list and eventually selling more than 35 million copies in fourteen languages; its actual argument concerned individual growth and outside friendships, with only one chapter, out of sixteen, raising sexual non-exclusivity as one possible expression of the idea (Wikipedia: Open marriage). Readers and reporters fixed on that chapter regardless, and "open marriage" came to mean sexual non-monogamy in popular use, a narrowing so complete that Nena O'Neill's 1977 follow-up book argued for sexual fidelity, and the couple later said they had never intended the concept for most marriages (Wikipedia: Open marriage). "Open relationship" itself is the more recent, marriage-neutral variant of the same phrase, spreading alongside the broader non-monogamy movements of the 1990s and 2000s.
How it works in practice
Couples in open relationships typically negotiate specific terms rather than operating on a blanket understanding, and therapists who work with these couples describe detailed, ongoing conversation as the load-bearing element of the arrangement. Sex therapist Susan Wenzel puts it directly: "Communication is lubrication to a relationship, meaning, the more you communicate, the more your relationship will flow with ease" (Katie Couric Media). Couples' therapist Gabrielle Usatynski recommends that partners "hash out every single last detail of what they're agreeing to," including terms for backing out if either partner grows uncomfortable (Katie Couric Media). Common negotiated terms include how much time outside involvement can take, whether the couple keeps having sex with each other, what safer-sex practices apply with outside partners, which acts are permitted, and how much detail gets shared afterward. Some couples run on strict rules (a fixed roster, a shared vetting step, no repeat partners); others agree only on broad limits and leave the rest to case-by-case judgment. A closely related but distinct arrangement, don't ask/don't tell, drops the disclosure step entirely: partners consent to outside involvement in principle but agree not to discuss the specifics.
Demographics & research
A 2012 U.S. National Survey of Sexual Health and Behavior found that 4% of partnered adult respondents described their relationship as open, against 89% monogamous and 8% non-consensually non-monogamous, figures the authors called conservative because they excluded anyone not currently partnered and any prior CNM history (Levine, Herbenick, Martinez, Fu & Dodge, 2018, Archives of Sexual Behavior). A nationally representative 2019 Canadian survey found much the same pattern: 2.4% of all adults, and 4.0% of adults currently in a relationship, reported currently being in an open relationship, with higher rates among gay and bisexual respondents than heterosexual ones (Fairbrother, Hart & Fairbrother, 2019, Journal of Sex Research). Interest runs well ahead of practice: a 2021 YouGov poll of over 23,000 U.S. adults found 25% would be interested in an open relationship, including 32% of men and 19% of women, and 30% of husbands against 21% of wives (YouGov). Placed against the wider pool of consensual non-monogamy, one nationally representative U.S. study found 21.9% of single adults reported some lifetime experience with a consensually non-monogamous relationship of any kind, open relationships included (Haupert, Gesselman, Moors, Fisher & Garcia, 2017, Journal of Sex & Marital Therapy).
Common misconceptions
An open relationship is not code for a relationship in trouble, and it is not the same thing as infidelity, since the defining feature is that both partners know and agree rather than one partner acting alone. It is also not identical to polyamory: an open relationship typically keeps one central couple and treats outside involvement as sexual rather than a second full romantic commitment, though the line blurs in practice for some couples. Nor is it identical to swinging, which the couple in an open relationship may or may not also do. Consenting to openness does not mean jealousy disappears: an early study of open-marriage participants found that roughly 80% experienced jealousy at some point despite having agreed to the arrangement, a finding regularly cited as evidence that these relationships take active, continued management rather than a one-time decision (Wikipedia: Open relationship).
Common questions
What is the difference between an open relationship and polyamory?
Where the romance lives. An open relationship keeps one couple as the emotional centre and permits sexual involvement outside it. Polyamory allows several romantic relationships that can each carry serious weight, with no requirement that one be the main one. The line blurs for couples whose outside connections deepen, which is one common route from the first into the second.
What is the difference between an open relationship and swinging?
Who does what, and where. Swinging is typically a couple's joint activity: partners participate together, often at organised events or with other couples. In an open relationship each partner generally pursues outside contact separately, on their own time. A couple can practise both, and many open couples never swing at all.
How common are open relationships?
Around one partnered adult in twenty-five, on the best national data. The 2012 US National Survey of Sexual Health and Behavior found 4% of partnered adults described their relationship as open, against 89% monogamous. A nationally representative 2019 Canadian survey found 2.4% of all adults and 4.0% of partnered adults. Interest runs far ahead of practice: a 2021 YouGov poll of over 23,000 US adults found 25% would be interested.
Does an open relationship mean you can sleep with anyone you want?
Almost never. Couples typically negotiate detailed terms: how much time outside involvement may take, what safer-sex practices apply, which acts are permitted, whether repeat partners are allowed, who is off-limits, and how much gets shared afterwards. Therapists who work with these couples describe that ongoing negotiation as the load-bearing part of the arrangement, not an optional formality.
Does opening a relationship mean it is in trouble?
Not by itself. The surveys find open relationships across ordinary demographics rather than concentrated among distressed couples, and the arrangement is generally negotiated from a stable position rather than as a rescue. Opening a relationship to fix an existing problem is what therapists warn against, which is a caution about timing, not a diagnosis of everyone who does it.
Do people in open relationships get jealous?
Routinely. An early study of open-marriage participants found roughly 80% experienced jealousy at some point despite having agreed to the arrangement, and the finding is regularly cited as evidence that these relationships require active, continued management rather than one decision. Consent removes the deception, not the feeling.
Consensual Non-MonogamyAn umbrella term for any arrangement in which everyone involved knowingly agrees that partners may have additional romantic or sexual relationships. That knowing agreement is what separates it from cheating.
MonogamishA predominantly monogamous relationship in which partners have negotiated narrow, specific exceptions to sexual exclusivity. Their primary romantic commitment to each other stays intact.
PolyamoryMaintaining multiple consensual romantic and/or sexual relationships at the same time, openly and with the knowledge of everyone involved. It is a relationship structure, not a sexual orientation.
Don't Ask, Don't TellA non-monogamous arrangement in which each partner may see other people, but both agree not to discuss those relationships. No questions asked, no details offered.
- Swinging57/100Acts & ActivitiesA form of consensual non-monogamy in which committed partners engage in sexual activity with others, often by exchanging partners. The exchange happens largely within a couple-oriented social scene. It is typically recreational rather than romantic.57
- Cuckolding66/100Troilism · Power, Roles & ScenariosA consensual erotic interest, sometimes termed troilism, in which a person is aroused by their committed partner's intimacy with someone else. The arousal can come from watching, knowing about, or imagining it. It ranges from humiliation play to affirming compersion.66
- Hotwife52/100Power, Roles & ScenariosA consensual-non-monogamy dynamic in which one partner takes pleasure and pride in their partner having other sexual partners. The first is called the "stag," the second the "hotwife" or "vixen." Unlike cuckolding, the framing centers on pride, admiration, and compersion rather than humiliation.52
- Group Sex78/100Acts & ActivitiesSexual interest or fantasy involving more than two consenting adults at once, from threesomes to larger gatherings. It is among the most reported fantasies and a consensual practice within negotiated, lawful settings.78
- Threesome70/100Acts & ActivitiesAn interest in consensual sexual activity involving three people at once, whether as a one-time encounter or a recurring arrangement. It is one of the most commonly reported sexual fantasies among adults.70
The phrase draws on "open marriage," a term sociologists and anthropologists used through the 1960s to distinguish marriages entered by free personal choice from "closed" marriages arranged along social or family lines. Nena and George O'Neill's 1972 bestseller Open Marriage: A New Life Style for Couples popularized the phrase under a different meaning (personal growth pursued outside a couple's shared identity, not sexual non-exclusivity), but a single chapter that floated the possibility of outside sexual involvement was what press coverage seized on, and by the later 1970s "open marriage" had settled into its present, narrower sense in everyday usage, a shift the O'Neills came to regret (Wikipedia: Open marriage).
Prevalence is computed from the entry's cited population estimate. Rows marked ESTare indicative editorial estimates scored against a fixed anchor rubric, not measured quantities. Method & anchors: methodology.
Common · ≈ 1 in 20
Basis: Two independent nationally representative surveys converge near 4% of partnered adults currently in an open relationship: the 2012 US National Survey of Sexual Health and Behavior (Levine et al., 2018, Archives of Sexual Behavior) and a 2019 Canadian population survey (Fairbrother et al., 2019, Journal of Sex Research, which found 2.4% of all adults and 4.0% of partnered adults).
- 01Levine, Herbenick, Martinez, Fu & Dodge (2018), Open Relationships, Nonconsensual Nonmonogamy, and Monogamy Among U.S. Adults, Archives of Sexual Behavior2012 NSSHB prevalence figures: 4% open, 89% monogamous, 8% non-consensually non-monogamous among partnered US adults.
- 02Fairbrother, Hart & Fairbrother (2019), Open Relationship Prevalence, Characteristics, and Correlates in a Nationally Representative Sample of Canadian Adults, Journal of Sex Research2.4% of all Canadian adults and 4.0% of partnered adults currently in an open relationship; definitional scope.
- 03Haupert, Gesselman, Moors, Fisher & Garcia (2017), Prevalence of Experiences With Consensual Nonmonogamous Relationships, Journal of Sex & Marital Therapy21.9% lifetime CNM experience among single US adults, used as wider population context.
- 04YouGov, Open relationships: how many people are interested, and does it differ by gender and sexuality?2021 poll of interest (not current practice) in open relationships, with gender breakdown.
- 05Katie Couric Media, Here's Why You Might Want to Try an Open RelationshipHow couples negotiate terms in practice; therapist quotes; distinction from polyamory.
- 06Wikipedia, Open marriage1960s sociological origin of the term; the O'Neills' 1972 book and its reception history.
- 07Wikipedia, Open relationshipDefinition, distinction from swinging and polyamory, and the ~80% jealousy finding among open-marriage participants.