https://royalsociety.org/news/2015/01/men-are-less-promiscuous-when-women-are-scarce/

TL;DR of article:

Scientists found that the gender ratio in communities affect men's promiscuity. Men are more promiscuous when there are more women in their community and less promiscuous when there are less women.

Scientists found women's promiscuity doesn't change in terms of gender ratio in communities.

No shit. This confirms the "men are polygamous, women are hypergamous" theory that TRP has.

Only reason why men would be less promiscuous when there are less women is because they want to be able to have sex. If they split with their mate, they get no sex. This, of course, doesn't matter when there are more women than men in a community since there's always "plenty of fish in the sea", and sex is easier to get.

Women's promiscuity doesn't change because they only mate with the alphas anyway.

TL;DR: Men need sex. Women need an alpha male.