One thought is that last I checked, romances are pretty popular with men, just not in the novel space-- in the anime/manga space plenty of men are obsessed with their risque romcoms, VNs are an entire genre which more or less thrive on being multiple choice romance novels (though there are some less romance centric, it's historically been practically required, see the history of fate/stay night). There's even a burgeoning transposition industry of the same tropes but applied to fantasy novels for straight men, replete with covers featuring the busty love interest.
I think part of this actually has to do with differing (social) gendered perspectives on what makes romances enjoyable/interesting.