Comment by JuniperMesos

I would guess that Adams probably wanted to have sex more than his girlfriend did, which meant that he had lots of personal experiences of his girlfriend not wanting to have sex when he did; and few if any personal experiences of not wanting to have sex when his girlfriend did. From his perspective, this looks like women (his girlfriend in particular) being the gatekeeper of sex. And this is what he was complaining about.

On a society-wide level, men are systematically more interested in having sex more often and in more contexts than women are. So lots of people in heterosexual relationships have experiences similar to Adams' (sex not happening in cases where the man wants it and the woman doesn't), which is why the rhetorical trope that women are the gatekeepers of sex exists.