I'm in a similar place myself; not long came out to my cis fiancé, mentioned to him that I'm seeking therapy, and that I don't think I can go through with surgery, even later on [well, bottom surgery is a no for sure, since I've had more majorly invasive surgery in my life than I'd like already, so 2 more would be out of the question.] I will consider top surgery, and I believe I told him that [if not yet, I will VERY soon when it comes up again] but I've been binding for a while anyway, for the best part of a year or thereabouts.
Basically, I've been diagnosed with moderate/severe depression because of my condition, and my fiancé knows this, and he's been responding well to the introduction of male underwear into my wardrobe. I dress mostly male anyway, always have done, ever since we met. I only went through a strap-top phase after being in hospital, because I got used to wearing them alot as they were the only thing I could change without having my Hickman line unhooked. xDD But thats another story.
Make sure to sit him down and have a good discussion with him about it. Try and make it clear that things don't change right away, even if you sought medical help. IF he truly loves you, he will stand by you and fight through his doubts to be with you whatever you do. Good luck.