I strongly dislike the two-men-compete-for-a-woman love triangle--for similar reasons to given by other commenters--but I do end up writing rather a lot of 'two men and a woman' triangulations, and at the moment a 'two women and a man' (unfinished). Usually the dynamic is that one of them feels only same-sex desire, one only other-sex, and the third's bisexual. There's sometimes a polyamorous arrangement. All of them are set between 1387 and 1416. I don't really know either, except Shakespeare histories fandom.

(Excuse my flippancy about flipping a coin--couldn't resist.)