hrj

The motif of "if I love a woman, I must (or would need to) be a man" is fairly common in pre-modern literary contexts--where we get access to what is presented as the individual's interior understanding. Examples off the top of my head would be Iphis & Ianthe, Yde & Olive (which easily come to mind since I've been writing up a blog including them). Classical Roman writers seem very prone towards this interpretation, with one vocal school taking the position that there is no class of "women who sexually desire women" but only a class of "women who are really men, and who therefore sexually desire (normal) women". The motif also shows up a fair amount in medieval and early modern court testimony in trials for "female husbands", although I take these with a grain of salt because at some times and places it seems to have been more acceptable to be judged a "hermaphrodite" (possibly intersex, possibly just toward one end of the bell curve on clitoris size) than to be judged a gender- and sexually-transgressive woman.

As you say, torn between wanting historic certainty and finding ambiguity more useful!