If I may add my story here...
...it's been difficult for me sometimes, being a lesbian in a relationship with a pre-operative MtF. (I'm androgyn yet identify as lesbian; figure that one out, people!

lol!) It took me awhile, but I enjoy being physically intimate with her, even though she has different equipment from what I'd prefer, simply because I love her.
I don't feel that she hinders or compromises my identity as a lesbian because she's still technically a man. (she is not fully out to everyone, and therefore appears as male 95% of the time.) My identity is inside of me, and doesn't have anything to do with anyone else but me. As far as the world is concerned, here's my response: Yes, I'm a butch lesbian and I'm kissing this guy. So what? She's a woman on the inside, and that's who I fell in love with. She's my girl no matter what's in her pants; that's MY business, not yours. lmfao
But Mrs. Cynthialee is right, at the end of the day it all boils down to "No matter what, I love her/him/hir. And I know he/she/zie loves me, too."