@bp I kinda feel you're all over the place here. I'd certainly suggest you change your handle on this forum. Yes your husband might have been presumed to be male but the fact is people change and marriage vows are about the individual, not their gender.
Also ask yourself if the reality of his being emotionally female isn't part of what attracts you.
Some sexual exploration is part of growing into being female for many of us, I explored bisexuality around the same time I first realized i was trans however I am absolutely more attracted to women and that's not changed or likely to. Also research has been quite positive showing late onset trans women are usually attracted to women both before and after transition.
No matter what age we have to address gender, it's usually a wrenching process. Also I don't view my partner as a support system it make her in any way responsible for my emotional state. If your husband is leaning on you more than you feel is appropriate, that's a disjoint problem from the fact of his transition. I would no more expect my partner to take responsibility for my stuff than fly to the moon.
[Edit]
Ok, realizing this is your fiance puts a slightly different spin on my thoughts clearly above I thought you were married. Also. I've had some sleep after 3 really hectic days so here are some more thoughts.
QuoteI wish that a meeting with a transgender person's SO was a requirement for all or part of their therapy and transition. While I realize that this is a personal choice- if most have "known" since birth, but chose to suppress it and live a lie, thereby essentially destroying another person (me) then I have to say that's pretty selfish.
That wish, I'm sorry is kinda ridiculous. I get that you're somewhere between the anger and denial stages of grief, however projecting your situation onto trans people generally seems off the mark to me. Whether addressed medically or not, being transexual is about the individual and the choice is up to the individual alone. Compare it to pregnancy: how to handle a pregnancy (including whether to abort) is the woman's choice. Sure, usually it will be discussed with their partner however under the law and firmly under any sensible ethical principles, the choices are the woman's.
Second, no person can complain that they are destroyed by another choosing what to do with their body. I'm sorry, again I can only take that statement as hyperbole.
Let me contrast to my experience, maybe put the shoe on the other foot. I was out with my partner (of now 19 years) beginning with our first date. I was relatively new to being trans (as in 3-4 months) and I daresay I knew somewhere in my heart how important it was to me so I wore lingerie under my date clothing because I felt I wanted to never address this after the fact. Our date consisted of dinner, going back to her place where I gave her her first over the knee spanking (we're both into fairly broad definitions of sex) and wound up in bed me wearing a silk thong and matching camisole.
I had no idea then that I would eventually want to transition, however having been up front from our first sexual experience, I felt kind of blindsided when, a year later I said I was considering it and was hit by a very self-centered "I'm not a lesbian" and a really strong push back. For that and other reasons I shelved transition for 16 more years and when I found myself dealing with deep depression and realized the time had come that I needed HRT and to explore GCS I wasn't surprised that I got the same push back, she acted like a hurt puppy for a couple if weeks and complained that she didn't want to be someone's support system (one consistent trait I love and hate about my SO is her stubbornness).
I found that complaint to be fairly spurious, I had weathered my deepening discontent with my body (and remaining "male" during my time away from home) solo. I hadn't bought the problem to her once as I slid into a depression for a couple of years and then battled my way out of it for a couple more because I knew pretty well what her response would be. The fact is, I'm a highly self reliant girl, it's not easy for me to lean on others, even when I should.
All that is now water under the bridge. My GF has in fact adjusted well to sex with a woman who now has a vagina that's replaced the penis she used to love and admittedly still misses. She also came to SF to help me with recovery post-op and I also relied on a couple of friends out there. If I could have physically managed that without help I would have, however I have to say needing to rely on her for a change and accept that post op I was pretty frail and battling mind numbing pain we're doses of humility that weren't bad experiences for me.
Back to you and your partner. Let go of anger and resentment; be assertive. Deal with the loss and consider what you might have to gain. Be a physicist, recognize that a glass is only empty if you pull a vacuum inside it and even then it contains space, makes reflections, etc.