Hi Pogo,
Your situation seems so familiar. I'm of course on the other end, mtf, wife, 8 month old son. I have no answer for you, but would like to share my story with you.
Like you, I have come to a point where I want/NEED nothing more than to transition for my sanity. I also want to spend the rest of my life with my wife but know she will never accept the woman she married. She did marry a woman, I just wasn't honest with her or myself at the time. I knew, I really knew about this since I was 5, just always thought I could subdue my inner woman and suppress the desire to transition.
I identify as lesbian and always have, just pretended I could live as a man. Impossible when you're about as feminine as you can possibly get pretending to be a man. I see a therapist who helped me acknowledge that this isn't going to go away and will just increase in intensity. It has year by year, month by month, and now week to week, day by day. It's so out of control at times I can't imagine living like this the rest of my life.
I feel such guilt and shame, not for who I am, I like me, but for the pain and suffering I know will be brought to my wife and son when I eventually have to make the transition that is inevitable. It is inevitable, and I figure I may as well start the process now, rather than in 2, 5, 10 years. It is just going to be harder on everyone the longer I wait. I love them more than anything and nothing makes me happier than being with them. The thought of losing them kills me.
When I think of transphobia and what it will do to stigmatize them and not just me the rest of their lives, I feel like a selfish bitch. Then I get reminded of how painful the dysphoria has become and feel there is no other choice. If only the world was accepting as most of us are here regarding gender identity.
Whatever decision you make, you are not alone, I found guidance here, found the perfect therapist through another girl here and am starting to sort this all out. The people you will meet here will never have all the answers, but they will support you and help you as best they can.
Amelia