I saw a discussion post a few days ago about whether a man's attitude toward casual sex matters or not. Luckily enough, I've had this post prepared for a week (it kept getting removed when I posted it maybe because of all the links to the studies in it, so I will comment all the links on this post instead). In short - always vet men for their past/present attitudes toward casual sex to save yourself the heartbreak, I will explain some science in this post.

Sociosexuality is an individual's attitudes toward casual sex, aka willingness to engage in sex outside of a committed relationship. Research shows that men who are unrestricted sociosexually (aka more open to hookups and casual sex) tend to have greater rape myth acceptance ("women make false accusations all the time") and histories of sexual aggression. These men also score higher on extraversion and impulsivity. They are much less likely to have a secure attachment style and much more likely to be avoidant attachment. Research has also found that the more committed a man is to you, the more strict he'll be about defining acts of infidelity. Think of all the men who follow instagram models or subscribe to another woman's OnlyFans - if he was truly committed he probably wouldn't be doing this and would categorize these acts under infidelity. Now, some male lurkers may read this and think "well, women are attracted to my player lifestyle so nice try, scrotesmadsosad. I can get away with all of that by being hot". Unfortunately for male lurkers and what some men might believe about casual sex and hookups making them more attractive, research has also found that women don't prefer men who are unrestricted sociosexually. They prefer sociosexually restricted men.

From a 2006 study, "Gender differences in the enactment of sociosexuality: An examination of implicit social motives, sexual fantasies, coercive sexual attitudes, and aggressive sexual behavior":

"For men, an unrestricted sociosexual orientation was linked with higher levels of rape myth acceptance and adversarial sexual beliefs; more conservative attitudes toward women; higher levels of power motivation and lower levels of affiliation‐intimacy motivation; and past use of sexual aggression."

From a 2017 study, "Sociosexuality, Commitment, Sexual Infidelity, and Perceptions of Infidelity: Data From the Second Love Web Site":

"Results showed that sociosexuality, alongside commitment, was associated with sexual infidelity. Individuals who had (versus had not) previously engaged in infidelity reported more unrestricted sociosexuality, while reporting less commitment. For individuals reporting prior sexual infidelity, unrestricted sociosexual desire and lesser commitment were associated with more permissive perceptions of infidelity. For individuals reporting no prior sexual infidelity, greater commitment was always associated with more strict perceptions of infidelity. No gender differences emerged in the analyses."

From a 2009 study, "Facial Correlates of Sociosexuality:

"Observers were generally able to identify restricted versus unrestricted individuals from cues in both composites and real faces...Although male observers did not generally associate sociosexuality with male attractiveness, female observers generally preferred more restricted males' faces (i.e. those with relatively strong preferences for long-term relationships). Collectively, our results support previous findings that androgenisation in men is related to less restricted sexual behaviour and suggest that women are averse to unrestricted men."