Markie,
Forgive me, but I haven't been part of any past interactions with you on this topic, but -- I wonder if you should think outside the box.
You're looking at a choice (a) between wife, children, current life on the one hand, and (b) therapist, potential gender change on the other. Due to a conflict, you are jettisoning (b) for (a).
But, perhaps you've framed the choice wrong. Could you move the therapist to door (a) for a while, and keep seeing him/her? Defocus the conversation with the therapist away from pure gender change (which wife sees as "bad") to management and understanding of your gender issues (which she should support).
And if you've already committed in your head to a gender change, living female 24x7, SRS and all that, it seems to me that you (bleep)ing need the therapist! Won't it be frustrating and lonely doing without? Can you really live with this totally in the background until the kids are off to college?
I just went through a divorce (oddly enough, not triggered by her "finding out", although she doesn't know), and I'm not out on the street with nothing. You may have a faulty assumption there. If you live in a community property state, you'll end up with about half of everything you own, and joint custody of the kids. Just because you are TS/TG doesn't automatically mean the court is going to treat you like an axe murderer.
It breaks my heart to think of you not only giving up what you want for your own future, but also cutting yourself off from the support you need in order to get through it.
Hugs,
Susie