Hmm. I'm not sure I've encountered (in my reading that is not nearly as broad as yours, I hasten to add) the notion of "if you love a woman, you must be a man" so much as "if you want to form a household and a life with a woman, you must be a man". (And probably "if you want to enjoy sexual pleasure with a woman, you must be a man" but there the scraps of information get very small indeed.) On the other hand, who knows how many women, especially bisexual woman, were discouraged from expressing romantic affection toward other women because marriage and overt romance were so impossible.

I am very torn between wanting definitive things as a researcher and being glad of places where I can safely make things up in my fiction!