The first girl I was [sexually active] with was pretty supportive of me. But then, I think it was deep down because she was happy I wanted to be a guy - she'd only ever dated guys before me and is dating one now, and I think I was more of a "take the opportunity because it's there" thing rather than a genuine interest. Ain't that a kicker.
Nooowww things are a lot trickier. I actually really like sex with my boyfriend but some days it's hard. He is a straight guy and so of course he's going to idealize the feminine parts of me.
My two cents: By the sounds of it it might be best for you both to move on. It's obvious she wants a girl from her comments towards you when you got your binder alone. You're not a girl and you will never be one, so it's fairest to both of you if you find what you each want and need in a relationship rather than dragging on something that causes discomfort to you.