I came out to myself just a little over a year ago, last August, and came out to my wife a couple of days later. I began to transition as soon as I could figure out what I could do and needed to do. We are together today, and stronger as a couple than we were before we started my transition. Will we make it? We hope so but do not know.
I think it helped us (even though it was very scary for us both) that I decided not to sugar coat what I had to say, and made a great effort to overcome my tendency to want to manage another person's reactions with the stakes are so high. It meant I was afraid she would leave me and/or our marriage would end, from day one, and many times since then, as I shared what I knew and what I felt, what I needed.
I read the accounts of many transitioners and their former significant others, and found one pattern was the attempt to gradually acclimate the spouse to this new reality, by slowly and tentatively expanding one's gender expression and stated needs. In almost every case that backfired, the spouse felt manipulated, lied to, controlled, betrayed, and doubted the sincerity and the intentions of the transitioner. His or her rage increased exponentially as the gender variance increased until reaching a flash point where the sig other gave the ultimatum: choose transition or me, or simply destroyed the marriage and tried to obliterate the transitioner.
I took a different path. From the very first night, I tried to be as "straight" - no pun intended - with my wife as I was with myself, and I tried to be brutally honest with myself. So when she asked me in a way that made clear what answer she wanted to hear, "do you think you are going to have the operation down there?" I said, 'I don't have any plans at this time but to be honest I have the strong feeling that I eventually will have to. It will be at least a year from now if I do because its a requirement that I live as a woman for at least a year. It will probably have to be a longer wait than that, but if my feelings don't change, I will need to do it as soon as I possibly can."
At another time, when she cut down my suggestions that she might explore bisexuality through her relationship with me, she gave me an ultimatum of a sort, saying "I will NEVER be a lesbian, I am NOT bisexual and don't want to ever be. If you have the operation I will never have sex with you again." I answered truthfully "Then when I have the operation, you and I won't have sex any more. That makes me very sad, but I respect your right to feel that way."
Another time, when she asked me if I was going to stop being attracted to her and start being attracted to men, I answered truthfully "I don't know. I don't think my attraction for you is based on my hormones or my anatomy, but only time will show if I am right about that. I can't imagine that I would stop being attracted to women completely, but I suspect I may be bisexual and just never expressed it. That being said, I don't know, because a lot of women who transitioned did find their feelings change."
When she asked me to slow down or postpone or stop various parts of my transition, I told her how that made me feel, and how I felt about stopping/postponing/slowing down. I told her no, I'm afraid I waited so long as it is that I am very fragile and need to transition as fully and as quickly as I can; that just thinking about slowing down brings the return of those feelings that made me want to end my life.
What helped her the most was when I stopped talking about transitioning and transitioned, with confidence and with determination.
The first night she saw me in full female dress, no wig on, but with basic make up, she said "oh my god! you are a woman. I couldn't picture it before, but your face, your eyes- I know this is the real you." She was able that night to make the leap in her mind and heart, and say "we are going to have a lot of fun together" and soon said "you are more beautiful to me as a woman than you were ever handsome as a man. I find you more attractive now. you are the person I married."
Starting hormones was not something that I asked her permission, since I would have to choose between defying her, and dying, when she said no or to go slow. I did tell her both before and after. It was another of those defining, turning points. In a week she was so impressed by my emotional transformation as I started the right gendered hormones for me, that she changed her own attitude towards HRT and we both went in for hormone lab tests. When she realized that her estrogen after menopause was lower than mine had been on my baseline labs before I started anything, she went to her doctor and started estrogen and progesterone.
We still have problems; I have overcome a lifetime of self-editing and self-denial, and have learned to have needs and to express them, to have emotions and to express them. If we fail to make it as a couple, it will not be because of the gender stuff, but because of underlying problems that were hidden when I was numb and playing a role that wasn't me. I am hopeful, but I live in that scary place of maturity that says "I want this relationship to last, as long as it is healthy for both of the people in it."