I empathize with you and your situation. I am similarly in a place where I have a mostly understanding and even supportive wife. I have been to the therapist and long story short — I am not gender fluid. I am a woman. Like you, I have spent a great portion of my life denying it, excusing it, creating barriers and more than likely many of the same language you have used to explain it away. Like you, I have not in so many words ‘come out” to my wife, but that is something we are inching towards. She has agreed to spend more time with me while presenting as my authentic self which is a big plus for us both.
In the end, there will be ups and downs. Questions. Doubts. Fears. And… not just from me. From her too. This not easy for me to be sure — just as it is not easy for you.
The way I have approached it with my wife is in a few different places. First — there is no need to worry about things that may or may not happen. Unless I come out and announce you are transitioning to full time here and now, my wife and I are choosing not to worry about that. I am not prepared to that point, and so no need to worry. The other important element I keep pressing is that we are both changing together. I think that is an important element to bring into all of this.
I really hope this all works out for you.