[tossmeout]

I can only speak to my own experience, but as a 20-something male (now in my early 30s) living in SF, there were a lot of societal norms pushing men to have more sexual encounters. It's somewhat of a badge of pride to achieve a "+1" which is code for sleeping with someone new. Forces like this can lead to men working harder to have sex with more people for its own sake. On the flip side, women have many opposing forces to contend with like "slut shaming," which don't affect men as much.

Additionally, being above or below someone's "league" is a bit of an oversimplification, because there are multiple axes to attraction. It's quite possible to be physically yet not mentally attracted to someone, and thus authentically enjoy sexual encounters with people who you'd prefer not to date seriously, let alone marrying.

If you accept both of these situations, it's not difficult to imagine a world in which many women are having sex with men where there's mutual sexual attraction but no possibility for a relationship, because the man is only interested in sex. Of course this happens the other way too, although I'd guess much less often.

An ex of mine (who I'd remained friendly with) once showed me her Tinder messages and it was full of attractive, confident, successful men who clearly were only interested in sex with her, and who didn't mind being almost offensively direct, presumably because they all had lots of other options for sex.