Opening a relationship to consensual non-monogamy vs staying strictly monogamous
Last reviewed 2026-05-30
Evidence quality 4.25/5
Eight-dimension review score against the
quality rubric
. Each dimension scored 1–5.
D1 Source verification
4/5
D2 Source authority & independence
5/5
D3 Regret-rate accuracy
2/5
D4 Source comparability
4/5
D5 Gilovich pattern
4/5
D6 Prose quality
5/5
D7 Caveat completeness
5/5
D8 Sample quality
5/5
Average4.25/5
Proxy data — no direct regret survey exists for this decision. Rates are derived from satisfaction scores and access-barrier data rather than questions that directly asked about regret. See caveats below.
Action regret
Opening to consensual non-monogamy
15%
~15% estimated regret rate for opening (proxy; no direct regret-of-opening survey; constructed from CNM-monogamy satisfaction parity plus elevated transition-period dissolution signal)
US adults who have engaged in CNM, online and convenience samples
cross-sectional, retrospective sentiment
Inaction regret
Staying strictly monogamous
21%
~21% of US adults report having engaged in CNM at some point in their lifetime — a revealed-preference floor on the share of monogamous adults who would regret never having tried (proxy)
US single adults, two nationally representative samples
lifetime, cross-sectional
% who regret this choice
Opening to consensual non-monogamyStaying strictly monogamous
15%21%
inaction dominates — Inaction dominates — most regret not acting.
Related decisions
Semantically similar decisions — same territory, different trade-offs.
Haupert, Gesselman, Moors, Fisher and Garcia’s 2017 study in the Journal of Sex & Marital Therapy, drawing on two nationally representative samples of single US adults (combined N=8,718), found that 21.9% in Study 1 and 21.2% in Study 2 reported engaging in consensual non-monogamy at some point in their lifetime, with the proportion stable across age, education, income, religion, region, political affiliation, and race. This 21% lifetime-engagement figure is used here as a revealed-preference floor on the inaction-side regret rate: at least this share of the US adult population has actually engaged in CNM, which traces a lower bound on the share of strictly-monogamous adults who would regret never having tried. The underlying pool of regret-curious-but-never-engaged adults — those constrained by partner agreement, social cost, or default inertia — is necessarily larger. No survey directly asks long-term monogamous adults “do you regret never having tried opening?”, so the 21% revealed-preference rate substitutes for the missing regret item. The OPEN 2025 Community Survey, conducted under Chapman University IRB by Dr. Amy Moors with 5,885 respondents from 65 countries, indicates that the CNM-identified population has grown substantially since the Haupert 2017 fieldwork, so the 21% should be treated as a conservative lower bound on current regret-curious population.
The action side — adults who opened their relationship and regret having done so — is the harder side to estimate. Conley, Matsick, Moors and Ziegler’s 2017 review in Perspectives on Psychological Science (PMID 28346120) synthesizes the comparative literature and finds few differences in relationship functioning between monogamous and CNM individuals. Conley, Piemonte, Gusakova and Rubin’s 2018 study in the Journal of Social and Personal Relationships reports that monogamous people report slightly lower sexual satisfaction and lower orgasm rates than CNM individuals, with swingers reporting higher sexual satisfaction than monogamous individuals and those in open relationships reporting equivalent satisfaction; relationship satisfaction did not differ between groups. Satisfaction parity is not the same as low regret, but it bounds the regret rate: if the average CNM participant reports satisfaction comparable to the average monogamous person, the lifetime-regret share among opened adults cannot be dramatically higher than the monogamy baseline. The 15% action-side estimate is anchored on this parity signal plus the well-documented elevated dissolution rate during the opening transition itself, which the cross-sectional satisfaction samples partly miss because dissolved CNM-attempting couples are absent from the currently-in-CNM populations.
The directional finding — inaction-side regret modestly exceeds action-side regret — is consistent with Roese and Summerville’s 2005 meta-analysis of 11 regret-ranking datasets, which identifies romance as the third-largest lifetime regret domain (14.8%) and finds inaction regrets persist longer than action regrets because they reflect greater perceived opportunity. A long-term monogamous adult who was curious about CNM but never explored falls squarely in the missed-opportunity-in-romance pattern. The delta is small (6 percentage points) and should be held loosely on magnitude: both rates are proxy constructions, the action-side rate is particularly speculative because no survey separates opened-and-stayed-open adults from opened-and-closed-again adults, and the published CNM-satisfaction literature faces non-trivial publication and researcher bias in both directions (Conley et al. document that polyamory-favorable findings face more bias accusations, while the field is dominated by CNM-sympathetic researchers). The r/OpenMarriageRegret subreddit with 16,000+ members is sometimes cited as evidence of high action-side regret; we have not used it because it is a self-selected community with no denominator. The 21%/15% rates are US-adult averages and do not generalize cleanly across gendered or orientation gradients — Haupert found higher CNM engagement among men and LGB respondents, so the regret-curious population is itself gendered.
Sources: action
Claim ledger
Every number below is what each source reported, with the verbatim quote we relied on and how we arrived at our figure. Click any link to verify directly.
[1]Journal of Social and Personal Relationships (Conley, Piemonte, Gusakova & Rubin) — Sexual satisfaction among individuals in monogamous and consensually non-monogamous relationships
Peer-reviewed
Across two samples, monogamous people reported slightly lower sexual satisfaction and lower orgasm rates than CNM individuals; relationship satisfaction did not differ between CNM and monogamous groups; swingers reported higher sexual satisfaction than monogamous individuals, while those in open relationships reported equivalent satisfaction
Excerpt
“"[Paraphrase from abstract — full text paywalled] Monogamous people reported slightly lower sexual satisfaction and lower orgasm rates than CNM individuals. Swingers consistently reported higher sexual satisfaction than monogamous individuals, whereas those in open relationships had equivalent levels of satisfaction to those in monogamous relationships. Relationship satisfaction did not differ between CNM and monogamous groups."
”
Source data from
2018-04-01
Accessed
2026-05-30
Calculation
Conley, Piemonte, Gusakova & Rubin (2018), Journal of Social and Personal Relationships 35(4), 509-531. DOI 10.1177/ 0265407517743078. Peer-reviewed comparison of sexual and relationship satisfaction across monogamous and CNM groups. Used here to establish parity: people who have opened are not systematically dissatisfied with their decision relative to monogamous comparators. Parity in satisfaction is not the same as low regret, but it bounds the regret rate: if the average CNM participant reports satisfaction comparable to or higher than the average monogamous person, the lifetime-regret share cannot be much higher than the monogamy baseline. The 15% action-side estimate is constructed from this parity signal plus the well-documented elevated dissolution rate during the transition period itself.
[2]Perspectives on Psychological Science (Conley, Matsick, Moors & Ziegler) — Investigation of Consensually Nonmonogamous Relationships
Peer-reviewed
Across a basic comparative analysis of monogamous and CNM relationships, few differences in relationship functioning emerged; researcher-bias analysis shows polyamory-favorable findings are accused of bias more than monogamy-favorable findings
Excerpt
“"[Paraphrase from abstract — full text paywalled] The premise that monogamy is the exemplary form of romantic partnership underlies much theory and research on relationship quality... We find few differences in relationship functioning between individuals engaged in monogamy and those in consensually nonmonogamous relationships."
”
Source data from
2017-03-01
Accessed
2026-05-30
Calculation
Conley, Matsick, Moors & Ziegler (2017), Perspectives on Psychological Science 12(2), 205-232. PMID 28346120. Peer-reviewed theoretical and empirical synthesis. Used as the methodological anchor for treating CNM and monogamous outcomes as comparable: the authors' core finding is that the assumed superiority of monogamy as a relationship configuration is not supported by direct comparison of functional outcomes. Establishes the empirical license to construct action-side regret as not systematically higher than the monogamy baseline.
Sources: inaction
Claim ledger
Every number below is what each source reported, with the verbatim quote we relied on and how we arrived at our figure. Click any link to verify directly.
[1]Journal of Sex & Marital Therapy (Haupert, Gesselman, Moors, Fisher & Garcia) — Prevalence of Experiences With Consensual Nonmonogamous Relationships: Findings From Two National Samples of Single Americans
Peer-reviewed
More than 1 in 5 (21.9% in Study 1, 21.2% in Study 2) of single US adults report engaging in consensual non-monogamy at some point in their lifetime; the proportion is stable across age, education, income, religion, region, political affiliation, and race
Excerpt
“"[Paraphrase from abstract — full text paywalled] More than 1 in 5 (21.9% in Study 1; 21.2% in Study 2) participants reported engaging in CNM at some point in their lifetime. This proportion remained constant across age, education level, income, religion, region, political affiliation, and race. The proportion varied with gender and sexual orientation: men and people who identify as gay, lesbian, or bisexual were more likely to report previous engagement in CNM."
”
Source data from
2017-04-20
Accessed
2026-05-30
Calculation
Haupert, Gesselman, Moors, Fisher & Garcia (2017), Journal of Sex & Marital Therapy 43(5), 424-440. Two nationally representative samples of single Americans (combined N=8,718). DOI 10.1080/0092623X.2016.1178675. The 21% figure is a revealed-preference floor on the share of US adults who would regret never having tried CNM: at least this fraction of the population has actually engaged in CNM at some lifetime point, and the underlying pool of adults curious about it but constrained by partner agreement or social cost is necessarily larger. The inaction-side regret rate is constructed by treating ever-engagement as a behavioural revealed preference — adults who have done it at least once are not the regret- of-monogamy population, but they trace the floor of the regret-curious population. The 21% rate is conservative because (a) it is conditional on singlehood at survey time, (b) it captures only realized engagement, not regret among adults who never engaged despite curiosity. Not a direct regret-of-monogamy measure.
[2]OPEN — Organization for Polyamory and Ethical Non-monogamy (Moors, Chapman University, IRB #26-13) — 2025 Community Survey Report
Reference source
5,885 respondents from 65 countries and 52 US states and territories — largest dataset of non-monogamous experiences compiled to date, conducted as formal academic research
Excerpt
“"The 2025 Community Survey gathered 5,885 respondents from 65 countries and 52 US states and territories, representing the largest dataset of non-monogamous experiences compiled to date. The survey was conducted as formal academic research in partnership with Dr. Amy Moors of Chapman University (IRB #26-13)."
”
Source data from
2025-04-15
Accessed
2026-05-30
Calculation
OPEN 2025 Community Survey — largest CNM-population dataset to date, conducted under IRB by Dr. Amy Moors. Used here as the anchor establishing that a large and growing population of US adults are CNM-active and willing to participate in academic research about their experiences. Not used for a direct regret-of-monogamy rate — the survey does not include retrospective regret-of-monogamy items because the population is already in CNM. Used as scaffolding for the claim that the Haupert 21% figure understates current CNM-curious population, because OPEN's 5,885 respondents represent a community of actively-CNM adults that has grown substantially since the Haupert 2017 fieldwork.
[3]Personality and Social Psychology Bulletin (Roese & Summerville) — What We Regret Most ... and Why↗ 12 other entries
Peer-reviewed
Romance is among the top three lifetime regret domains (14.8%); regrets of inaction persist longer than regrets of action because they reflect greater perceived opportunity within affected life domains
Excerpt
“"Regrets of inaction persist longer than regrets of action in part because they reflect greater perceived opportunity. Education (32.2%), career (22.3%), and romance (14.8%) top lifetime regret domains; the common thread is missed opportunity for self-actualization."
”
Source data from
2005-09-01
Accessed
2026-05-30
Calculation
Roese & Summerville (2005), PSPB 31(9), 1273-1285. Foundational meta-analysis. The romance domain consistently ranks in the top three regret categories across 11 datasets, and the inaction-dominant pattern (84% of biggest-regrets are inactions per Gilovich & Medvec 1994) applies particularly to romance because the opportunity window closes with partner commitment. Used as theoretical anchor: a long-term monogamous adult who never explored CNM despite curiosity falls squarely in the missed-opportunity-in-romance-domain pattern, which Roese and Summerville identify as the most regret-generative category. Supports the directional finding that inaction-side regret modestly exceeds action-side regret in this dilemma.
Caveats
PROXY MEASUREMENTS THROUGHOUT. No published survey directly asks US adults "do you regret opening your relationship?" or "do you regret staying monogamous?" The 15% action-side rate is constructed from CNM-monogamy satisfaction parity findings (Conley et al. 2017, 2018) plus the well-documented elevated dissolution rate during the opening transition itself. The 21% inaction-side rate is a revealed-preference floor anchored on the share of single US adults who have actually engaged in CNM at some lifetime point (Haupert et al. 2017, combined N=8,718 across two nationally representative samples). Neither rate is a direct regret measurement.
SATISFACTION PARITY IS NOT REGRET PARITY. The Conley et al. (2018) finding that CNM and monogamous individuals report comparable relationship satisfaction is the strongest empirical anchor for the action-side rate, but satisfaction parity bounds regret rather than measuring it. The transition period — the months and years immediately after opening a previously-monogamous relationship — is the highest-regret window, and the cross-sectional Conley samples include adults who survived that transition. Selection bias likely understates transition-period regret: dissolved CNM-attempting couples are partly absent from the currently-in-CNM samples.
SUBREDDIT EVIDENCE IS NOT REPRESENTATIVE. The r/OpenMarriageRegret subreddit (16,000+ members) is sometimes cited as evidence of high action-side regret; we have not used it because it is a self-selected community for people specifically experiencing regret, with no denominator. The forum's existence indicates that regret-after-opening is a recognizable phenomenon, but says nothing about its population-level rate.
PUBLISHED CNM SATISFACTION LITERATURE FACES PUBLICATION BIAS. Conley et al. (2017) explicitly document that polyamory-favorable findings face more bias accusations than monogamy-favorable findings, and the authors argue the field's monogamy-default inflates published evidence for monogamy's superiority. The parity finding may therefore be conservative. On the other side, the CNM-research literature is dominated by researchers sympathetic to CNM, which may pull in the opposite direction. We treat the satisfaction-parity finding as directionally robust but not magnitude-precise.
GENDER AND ORIENTATION GRADIENT. Haupert et al. found higher CNM engagement among men and LGB respondents; the 21% headline rate is the cross-cohort average and the regret-curious population is gendered. Heterosexual women, who underrepresent in CNM engagement at all life stages, may also underrepresent in inaction-side regret. The 21% should be read as a US-adult average, not a per-demographic rate.
RECENT GROWTH IN CNM VISIBILITY. The OPEN 2025 Community Survey (N=5,885) — the largest CNM-population dataset to date, conducted under Chapman University IRB by Dr. Amy Moors — shows substantial growth in identified-CNM population since Haupert's 2017 fieldwork. The Haupert 21% lifetime-engagement figure is therefore a conservative lower bound on current CNM-curious population.
