People with more partners more likely to cheat?
Executive summary
Multiple peer-reviewed studies and large surveys report a consistent correlation: people who report more past sexual partners also report higher rates of later infidelity, but the relationship is complex and not strictly causal—personality, sexual desire, opportunity, and even genetic factors help explain the link, while measurement limits and social biases complicate straightforward interpretation [1] [2] [3] [4].
1. What the data actually show: a repeated correlation, not proof of causation
Several lines of empirical work find that higher numbers of prior sexual partners are associated with greater likelihood of extradyadic sex later on—for example, a survey analysis reported that people with five or more lifetime partners had roughly double the infidelity rate in marriage compared with those reporting four or fewer partners (21% vs. 11%) [1], and a meta-review and cohort studies repeatedly list lifetime partner count among predictors of infidelity [5] [4]. Twin and genetic designs add nuance by showing a substantial heritable component to both number of partners and infidelity and a strong genetic correlation between them—suggesting shared predispositions rather than pure behavioral carryover (41% heritable for infidelity, 38% for partner count, with a 47% genetic correlation in one large UK twin study) [3] [6].
2. Mechanisms that could link past partners to later cheating
Researchers propose multiple, non-mutually exclusive mechanisms: "practice" and habituation to short-term mating strategies (attitudes and behaviors that make opportunistic sex more likely), stable sexual personality traits such as high sexual excitation/low inhibition and certain Big Five dimensions (extraversion, low conscientiousness, high neuroticism), and greater sexual desire or opportunities that persist across relationships [1] [2] [4]. The dual-control model of sexual response and studies using SES/SIS scales show that sexual excitation and inhibition predict infidelity risk beyond simple demographics, meaning prior partner count may proxy for enduring propensities [2] [4].
3. Confounders, measurement problems, and alternative explanations
Important caveats weaken a simplistic reading: most findings are correlational and rely on self-report surveys that vary in how they define “cheating” (emotional vs. sexual), which can undercount or misclassify events [7] [5]. Background variables—education, religion, urbanicity, relationship type and commitment level—also correlate with both partner counts and infidelity risk, so raw associations attenuate when controls are added in some analyses [5] [8]. Moreover, reporting biases and changing social norms over time make cross-cohort comparisons fraught [5] [7].
4. What the strongest multivariate studies say about predictive power
When researchers model multiple predictors simultaneously, personality and sexual-response measures often explain more variance in infidelity than simple demographics like marital status or religiosity, indicating that individual dispositions matter and that partner count is only one piece of the puzzle [2] [4]. The Institute for Family Studies analysis emphasizes durable differences in attitudes and behaviors among those with many partners—such as greater acceptance of sex without love—which plausibly mediates higher later infidelity rates, but that organization has an explicit interest in family stability that readers should note when weighing interpretation [1].
5. Bottom line and practical implications
The evidence supports a clear empirical association: people with more prior partners are, on average, more likely to report cheating later, but that association reflects a mix of behavioral practice, enduring personality/sexual-response traits, genetic predispositions, and differing social contexts rather than a simple causal effect of “body count” itself [1] [3] [2]. Given measurement limits and varying definitions of infidelity, conclusions should be probabilistic: partner history is a risk marker, not destiny, and the strongest scientific models point to broader dispositional and relational factors as the active mechanisms [2] [4] [7].