I have seen reports of sexuality changing by those who have gone through a transition using hormone replacement therapy and sexual reassignment surgery.
I would suggest talking about it and setting ground rules for how far you can go.
I'm transgender but agreed not to go on HRT unless we had a discussion on the matter. HRT will certainly affect your sexual abilities.
An honest discussion and setting ground rules will help your relationship no matter what your sexuality. Which is actually separate from your gender.