I commend your efforts at being understanding. I can't imagine how hard your position must be...
Judging from your posts, there's a lot you aren't ready for, or comfortable with... I hope that you've never felt like you're "supposed" to be comfortable with certain things just to make someone else happy. I don't think that could ever work...
Your husband's gender issues are his own... You choose to support him, but please watch over your own emotional well-being, don't let it get to the point where his issues take control of your life... I know, it's easy for me to talk...
I've never gone through what you're going through, but I've been tormented by emotional grief before. If you're ever at a point where this is all you can think about and it's making you angry, try to distance your mind from it. Escapism, literally... Find something that lets you direct your thoughts away from it. It might seem like the end of the world, but it's really not... It's awful to be stuck "mourning" over the "loss" of something, but instead of dwelling on that, try to take time for yourself, get some distance between you and the problem.
I don't know the extent of your husband's gender issues, but, they're apparently serious enough to affect your marriage... from what I know and experienced, most people with intense gender dysphoria will not be satisfied unless they fully transition, they'll grow increasingly unhappy and resent the world.
He says he doesn't want to feminize himself or start any hormone treatments, but, does he want to feel like a woman? In what kind of setting? Unless this is some sort of sexual fetish for him, I'm skeptical about the thought of a more feminine appearance not crossing his mind. If he has the need to see himself as a woman sometimes, I find it hard to believe that his mental portrayal of that woman wears a dress while sporting a five-o-clock shadow.
No woman fantasizes about being burly or looking weird...
When I took my first steps at transitioning, it was much easier to convey to people that I was androgynous, than to tell them that I really could only function and be socially comfortable as a girl. Specially to people that had known me for a long-time, there was an element of shame around it, a fear of being a disappointment, having my feelings hurt by others' opinions, etc.
If you're not remotely flexible in your sexual orientation, then please, for your sake, try to always be aware of what's going on in his head as this situation progresses, to make sure that he withholds nothing. It's probably hard for him to be open, specially to someone that he loves and fears rejection from. I told my parents the "don't worry, I don't want boobs" line plenty of times. I did it because they were never reasonable with me, if they expressed contempt towards me owning a skirt, they obviously wouldn't be thrilled by the idea of me having to wear a bra...
I did the smart thing for me, I omitted what would make them uncomfortable and slowly pushed their boundaries until I got what I wanted. One day it was the clothes, the other day it was the hair... suddenly there was nothing weird about me having breasts anymore.
If you are unsure about what his milestones are, I think you should ask him in a situation where he feels comfortable opening up about his feelings. Being cool, showing no hints of being upset, displaying empathy... I think those promote complete honesty...
I hope I'm not alarming you, I'm just trying to suggest that hoping for the best while being ready for the worst is a good defense mechanism, it'll shield you from the possibility of feeling disappointed again.
It's quite possible that he just wants to be androgynous and finds his inner peace there. There's girly girls, there's tomboys, there's manly boys and femboys... Gender seems to be a spectrum, it doesn't deal with just two polar extremes, so, gender dysphoria doesn't really imply a need to be on either one end or the other...
Just be aware that his feelings and goals might also change overtime. I think the tendency would be for him to be more comfortable exposing them to you.
In the end, he has a problem that he's trying to find an answer to, and, sadly you were dragged into it. I'm hoping that you can always be honest with yourself, regarding what you're sure to be okay with and what you might not like... I'm sure the situation will get easier overtime, as long as you assess if this relationship will fulfill you in the future, and if his direction in life makes him happier.
I wish you both the best, you undoubtedly care about each other a lot =)
