Sociosexuality and Infidelity: What the Research Really Says

October 5, 2026 · 5 min read

What Is Sociosexuality, and Why Does It Get Linked to Infidelity?

Sociosexuality describes how willing a person is to engage in sexual relationships without closeness, commitment, or deep emotional connection. Researchers measure it along a continuum—from restricted, where sex and emotional bonds are tightly linked, to unrestricted, where the two are more separable. If you have taken the SOI-R quiz, you already have a sense of where you fall on that spectrum.

Because unrestricted sociosexuality involves an openness to casual sex, it is easy to assume a straight line runs from a high score to cheating. That assumption deserves careful scrutiny. The relationship is real in a limited sense, but it is far more conditional and complicated than popular accounts suggest.

Association Is Not Causation

Research consistently finds that people with more unrestricted sociosexual orientations are, on average, more likely to report having engaged in infidelity at some point in their lives. That association is well-documented. But an association tells us only that two things tend to travel together—it says nothing about one thing producing the other.

Consider that many other variables are associated with infidelity in overlapping ways: relationship dissatisfaction, impulsivity, sensation-seeking, and situational opportunity, among others. Sociosexuality is tangled up with several of those same traits. When researchers attempt to hold those other factors steady, the direct contribution of sociosexuality to infidelity becomes much harder to isolate. The signal is there, but it is not clean.

This matters because causal language—"unrestricted people cheat"—implies a mechanism and a near-inevitability that the evidence simply does not support. Describing an association is honest; treating it as a causal verdict is not.

The Decisive Role of Commitment

Perhaps the most important moderating factor is relationship commitment itself. Sociosexuality describes an orientation—a baseline inclination—but inclinations interact with context. When a person with an unrestricted orientation is deeply invested in a relationship, that investment exerts its own influence on behavior.

Research on the SOI-R's three components—behavior, attitude, and desire—is instructive here. Desire and attitude can remain elevated even in someone who has chosen a committed partnership and genuinely values it. A person can find others attractive, hold relatively permissive attitudes about casual sex in the abstract, and still maintain fidelity, because commitment functions as a governor on behavior. The desire component of the SOI-R in particular captures something closer to fantasy and inclination than to behavioral intention.

This is why the SOI-R statistics are best understood at the population level, as descriptions of tendencies across groups, rather than as predictions about what any individual will do. Orientation and behavior are related, but they are not the same thing.

Opportunity Shapes Outcomes More Than Scores Suggest

Even a strong unrestricted orientation requires opportunity to translate into infidelity. Social environment, relationship structure, and daily circumstances all shape whether a tendency ever finds expression. Someone who travels extensively for work, socializes in contexts with high partner availability, and has a peer group where infidelity is normalized faces a very different landscape than someone whose daily life offers few such openings—even if the two people have identical SOI-R scores.

This is a point that purely dispositional accounts miss. Behavior is always the product of the person and the situation. A score on the SOI-R captures something about the person; it captures nothing about the situation. Treating the score as a prophecy ignores half the equation.

Why a High Score Is Not a Prophecy

It is worth being direct about this. A high SOI-R score does not mean someone will be unfaithful. It means that, compared with lower-scoring individuals, they tend to place less weight on emotional closeness as a prerequisite for sexual interest, and that they may have had more short-term partners in the past. That profile can coexist with full commitment to a monogamous relationship, particularly when that commitment is chosen freely and valued genuinely.

Researchers who developed the SOI-R were careful to design a measure of orientation, not of moral character. The inventory was built to capture stable individual differences in how people approach sexuality—differences that appear to have both biological and cultural roots. Nothing about the scale's design or validation frames a high score as a warning sign.

A More Useful Frame

Rather than asking "do unrestricted people cheat?" a more productive question is: under what conditions does a mismatch between sociosexual orientation and relationship structure create friction? Mismatches—where two partners have very different orientations, or where a relationship's implicit rules conflict with a person's natural inclinations—are likely to be more predictive of problems than any raw score on its own.

Sociosexuality is a useful lens for understanding individual differences in how people relate to sex and intimacy. Like most psychological traits, it illuminates tendencies, not destinies. Using it as a tool for self-understanding, rather than a sentence, is precisely what the research supports.

References

Penke, L., & Asendorpf, J. B. (2008). Beyond global sociosexual orientations: A more differentiated look at sociosexuality and its effects on courtship and romantic relationships. Journal of Personality and Social Psychology, 95, 1113–1135.

Simpson, J. A., & Gangestad, S. W. (1991). Individual differences in sociosexuality: Evidence for convergent and discriminant validity. Journal of Personality and Social Psychology, 60, 870–883.