Hey Jin.
First off, I can understand where you're coming from on the gender identity front.
This relationship that you are describing is starting to sound abusive. Although he isn't quite there yet, it seems like pretty soon he'll see you as more of an object as a person, which isn't right (unless it's an S+M type relationship, which I'm guessing it isn't). You shouldn't feel obligated to have sex with him, and he shouldn't feel entitled to sex with you either, especially if he doesn't except you for who you are.
The first thing you need to do before you figure out anything else is get out of that relationship. Do you have any friends you can stay with? I know you said you can't live on your own, but if you have a way of getting an income you could find a new roommate somewhere else. You said that you got fired from your jobs due to mental illness, which I'm sorry to say I can't really give advice for, though I hope you could find a way to work things out. However, since you have a mental illness, do you have a therapist that you could also talk through this issue with? There are also places like free clinics that could help you, and some shelters that provide housing to people who can't afford it if things turn for the worse.
Your other only option is to find a way to fix your relationship with this guy. Not in the sense that you get back together and get married per se, but so that he understands that he can't take advantage of you. Does he know that you aren't just a masculine girl, but identify as male? You said that he didn't like to be near you when you crossdressed for your anime cosplays at conventions, maybe this could put him off as well?
If you have other questions or need more advice, I'd be happy to talk to you more, but hopefully something from here can help you out. I really wish you a lot of luck, and I admire you for figuring out who you are when people are scared of admitting their gender issues to themselves.