So, apparently about a third of young men aren't having sex.
https://m.youtube.com/watch?v=HWGJRrZnq-U
I take this all with a grain of salt, but personal experience aligns pretty well with the findings.
I'm 29 and haven't had sex since 2011. Partly out of not making much of an attempt, and partly due to losing my looks prematurely.
Interestingly, I've received several sexual advances from gay men, but these specific individuals weren't appealing to me. Not to needlessly generalise, but men in general tend to be less discerning than women.
It also seems that a lot of women around my age have a preference for men ten to twenty years older than they are. I checked Facebook, and found that about half of my previous partners were with much older men.
I wonder if there's some generational difference between Gen X guys and millennials. In my personal experience Gen Xers tend to be more outgoing, assertive and direct.