If age gap relationships were societally common what would younger guys do ?

I often hear that an age gap relationship is optimal, Plato for instance emphasized the fact that the ideal age for marriage was 42 for men and 18 for women (a bit weird I know).

Which technically does make sense, older guys are at the peak of their value and younger women are at the peak of their fertility, I can get the logic here. I heard that it happened a lot in prehistorical societies and indigenous societies.

However what I was wondering here was that if it became societal then what would younger guys do. Sleeping around won’t make sense since all the women would be taken by older guys, so would they get mad or would they stay virgin until 35. Apparently it was common in the past so its interesting to know the answer.