If they really love you, they’ll understand that you have this feminine side and come to terms with it.
Indeed, if they really take time and get involved in your transexual side they might find that you’re the best damn girlfriend they could have. Sex isn’t necessarily part of this.
Friendship and love is so much more than sex.
Go and explore, and keep in mind that you’re a wonderful woman inside, but so is your wife, and don’t hurt her to make a point.