I know there are a lot of complex issues in your post (and also Hellokitty's comment), but the one thing that stood out to me in both of your situations is that your male partners' lack of interest in sex. It is going to have a compounding affect. I mean you've got these new lovers who are totally hot for you, and your long term partners complaining that they feel pressured when you ask for sex. That's a problem. While I know there is added confusion because of the gender differences, I would hazard a guess that if your new partners were men or your old partners were women, you might feel much the same. Sexual incompatibility is huge.
Sorry, I know that doesn't address your question, but perhaps the question of whether you are gay is not really pertinent. It may be all about having a lover that matches your libido.