How Common Is Consensual Non-Monogamy? What Studies Report

Consensual non-monogamy often feels like a hidden world, but a growing body of research shows it is more common than many people assume. From national surveys to community studies, data paints a picture of millions of people exploring open relationships, polyamory, and swinging. Here is what the numbers tell us about how many people practice or desire these relationship styles.

What Do We Mean by Consensual Non-Monogamy?

Before diving into the numbers, it helps to clarify the term. Consensual non-monogamy, often shortened to CNM, describes any relationship where everyone involved openly agrees to romantic or sexual connections outside the primary partnership. This umbrella covers several distinct styles, with swinging, polyamory, and open relationships being the most researched and widely recognized forms^[1].

Swinging typically involves couples engaging in sexual activities with others, often in social or event-based settings. Polyamory emphasizes multiple loving, emotional bonds with the knowledge and consent of everyone involved. Open relationships generally refer to a committed couple allowing outside sexual experiences while maintaining their primary emotional connection. These categories can overlap, and many people blend elements to suit their unique needs.

What unites all these approaches is consent. Unlike secret infidelity, CNM relies on ongoing communication, negotiated boundaries, and mutual respect. Understanding this foundation makes the prevalence data more meaningful—it reflects people intentionally choosing relationship structures that work for them.

How Many People Are Currently in CNM Relationships?

Point-in-time estimates give us a snapshot of active participation. Research consistently suggests that a small but significant minority of adults are in consensually non-monogamous relationships at any given moment. In the United States, estimates place this figure between 3% and 7% of the population^[1]. Similar patterns emerge internationally: about 2.5% of Canadians, around 3% of Norwegians, and roughly 3.3% of Dutch and Flemish adults report current CNM involvement^[1].

A closer look at specific groups sharpens the picture. A 2017 nationally representative survey of Canadian adults found that 2.4% of all participants were in an open relationship, and among those currently in any relationship, the number rose to 4.0%^[5]. In the United States, a 2018 study focusing on swinging reported that 2.35% of Americans identified as swingers at that time^[3]. Psychologist Jessica Fern noted in 2020 that about 4% of Americans, translating to nearly 16 million people, were practicing some form of non-monogamy^[2].

These percentages may seem modest, but they represent millions of individuals quietly living out relationship choices that differ from the monogamous norm. The consistency across Western countries suggests CNM is not a fringe phenomenon but a stable minority experience.

Lifetime Experience: A Much Larger Picture

When researchers ask whether people have ever engaged in consensual non-monogamy, the numbers grow substantially. Around a quarter of Americans, Canadians, Norwegians, and Dutch and Flemish adults report having been in a CNM relationship at some point in their lives^[1]. This suggests that while current participation hovers in the single digits, many more people have explored non-monogamy at least once.

Two large U.S. studies using census-based quota samples of single adults reinforce this finding. In one sample of 3,905 individuals, 21.9% reported lifetime CNM experience; in a second sample of 4,813 individuals, the figure was 21.2%^[4]. The consistency across these independent samples strengthens confidence in the estimate. Similarly, a 2017 Canadian study found that one-fifth of participants had previously been in an open relationship^[5].

A 2021 study by Moors, Gesselman, and Garcia, which surveyed 3,438 people, found that 10.7% had been in a polyamorous relationship at some point, while 16.8% expressed a desire to try or be in one^[2]. The gap between experience and interest hints that curiosity about polyamory may outpace actual practice, at least for now.

Swinging also shows a notable lifetime footprint. In the 2018 U.S. prevalence study, 4.76% of Americans had identified as swingers at some point, roughly double the current participation rate^[3]. This pattern—lifetime numbers exceeding current ones—makes intuitive sense. Relationships evolve, and people may move in and out of non-monogamous arrangements as their circumstances, desires, and partnerships change.

Who Explores CNM? Demographic Patterns

One of the most striking findings from recent research is how evenly lifetime CNM experience is distributed across demographic groups. In the U.S. single adult samples, the proportion of people who had tried consensual non-monogamy remained constant regardless of age, education level, income, religion, region, political affiliation, or race^[4]. This suggests that curiosity about non-monogamy is not confined to any particular social niche.

Some differences do emerge. Men were more likely than women to report previous CNM engagement in both U.S. and Canadian studies^[4][5]. People who identify as gay, lesbian, or bisexual also reported higher rates of CNM experience compared to heterosexual individuals^[4]. These patterns may reflect varying social norms, opportunities, or willingness to disclose non-traditional relationships.

Age plays a nuanced role. In the Canadian sample, younger participants were more likely to engage in open relationships and to prefer them as an ideal relationship type^[5]. Yet the U.S. single adult data showed no age differences in lifetime CNM experience, indicating that older generations have also explored these paths, even if they used different language or were less visible^[4].

Educational background shows a curious twist. The 2021 polyamory study found that lesser-educated male individuals were more likely to have engaged in polyamorous relationships, challenging assumptions that CNM is exclusively a phenomenon of highly educated urbanites^[2]. Meanwhile, a 2023 study of German swingers found no clear link between swinger prevalence and regional socioeconomic factors, though BDSM-affiliated swingers and those in open or polyamorous relationships tended to concentrate in urban areas^[6].

Shifting Ideals: How Many People Want Non-Monogamy?

Beyond current behavior and past experience, researchers have started measuring relationship ideals. The numbers here suggest a significant appetite for alternatives to strict monogamy. A YouGov poll in 2020 found that about one-third of U.S. adults believed their ideal relationship was non-monogamous to some degree^[1]. In 2024, a similar poll in Britain reported that 9% of respondents had been or would like to be in a polyamorous relationship^[1].

The Canadian data offers another angle: 12% of participants identified an open relationship as their ideal type, and men were more likely than women to hold this preference^[5]. Younger participants also showed a stronger preference for open relationships, hinting at a possible generational shift in attitudes^[5].

Importantly, having a match between one's actual relationship structure and one's preferred structure appears to matter for well-being. The Canadian study found that relationship satisfaction did not differ significantly between monogamous and open relationships, but alignment between reality and ideal was associated with greater satisfaction^[5]. This underscores a practical truth: no single relationship model works for everyone, and the key is finding what genuinely fits.

A Look at Swinging Communities

Swinging, as one of the more established forms of CNM, has attracted its own body of research. A 2023 study of Germany's heterosexual swinger community analyzed 22,973 self-declared swingers and found a median age of 44 for women and 46 for men^[6]. This suggests that swinging often appeals to people in midlife, perhaps after they have established long-term partnerships and are seeking new shared experiences.

The same study examined 14,008 attendees at 82 swinger events and observed several interesting patterns. Events were strongly focused on women's preferences, with some specifically targeting younger male partners. A prominent presence of solo women was noted, contradicting earlier findings from other countries that suggested swinger spaces were predominantly couple-focused^[6]. Reduced pricing for women at these events did not correlate with higher attendance, challenging common assumptions about what drives participation^[6].

Health considerations are part of the swinger landscape. A Dutch study comparing medical records found that STI prevalence was higher among swingers than the general population, with combined chlamydia and gonorrhea rates of 10.4% among swingers, compared to just over 10% among straight people and 14% among gay men^[3]. This data highlights the importance of regular sexual health check-ups and open conversations about safer sex practices. A 1992 study found that 62% of swingers had changed their sex practices in response to the HIV/AIDS epidemic, becoming more selective with partners or adopting safer sex methods^[3].

On the positive side, a 2000 study based on an internet questionnaire for visitors of swinger-related sites found that swingers reported higher relationship happiness than the norm^[3]. While self-selected online samples have limitations, the finding aligns with the broader pattern that consensual non-monogamy, when practiced with communication and mutual agreement, can be compatible with satisfying relationships.

Historical and Cultural Context

Today's CNM practices are not a modern invention. A 1990 study of pre-colonial Polynesian cultures examined relationship structures across 127 groups and found that consensual non-monogamy was the norm in 97 of them^[2]. This historical perspective reminds us that human relationship diversity is ancient and widespread, even if contemporary Western societies have centered monogamy as the default.

Research also suggests that CNM arrangements are becoming increasingly visible in Western societies^[1]. The growing body of academic studies, media coverage, and community resources reflects and accelerates this visibility. As more people encounter the language and concepts of open relationships and polyamory, the numbers who identify with these labels may continue to shift.

An article on what psychology professionals should know about polyamory notes that while openly polyamorous relationships are relatively rare, there are indications that private polyamorous arrangements within relationships are actually quite common^[2]. This gap between public identity and private practice is a recurring theme. Many people may negotiate non-monogamous agreements without adopting specific labels or joining visible communities.

Making Sense of the Numbers

So how common is consensual non-monogamy? The answer depends on the question you ask. At any given moment, roughly 3% to 7% of adults in Western countries are actively practicing some form of CNM^[1]. Over a lifetime, that number jumps to about one in four people^[1][4][5]. When you include those who desire or are curious about non-monogamy, the figures climb even higher, with up to a third of U.S. adults saying their ideal relationship is non-monogamous to some degree^[1].

These statistics carry practical implications. If you are considering CNM, you are far from alone. Millions of people have navigated similar questions, and a wealth of lived experience and research now exists to inform your path. At the same time, numbers do not dictate personal choices. The goal is not to follow a trend but to build relationships rooted in honesty, consent, and mutual care.

If you are exploring these options, consider starting with open conversations about what non-monogamy means to you and your partners. Discuss boundaries, safer sex practices, and how you will handle jealousy or scheduling challenges. Seeking out supportive communities, books, or therapists familiar with CNM can provide guidance without pressure. And remember that relationship structures can evolve—what works at one stage of life may shift, and that flexibility is part of the journey.

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