Hi Echo!
I'm sorry, I just wanted to see if I could understand your situation: your boyfriend cd's and you're all right with it, but you're not sure how to explain to him that you would like to transition to a gender that is not what you were physically born with?
To me, it sounds like there are many serious conversations that need to happen for clarification for both of you. I know that the paths you will take are unique to each of you, but certainly you can share the road and enjoy each other's comfort.
Good luck! I don't know how difficult it is, but I know what it is to love someone so much that the result of you two being together is all that matters.
S.