I guess my case is somewhat different. My wife first became aware of my "condition" when we were married almost 2 years and I attempted suicide. After that, we talked about it, but I was still terrified of the implications and all too willing to try to run from it, so we managed to bury it, and I spent the next 30 years in denial while we raised 3 kids. Earlier this year, after yet another attempt to resolve the long-standing marital issues between us, I realized that my trans status was still an issue for me (thought it was dead and buried long ago), and decided in order to have any chance at real happiness and intimacy I had to face it once and for all.
Since that time, as I've progressed towards transition, my wife grows more distant, and we are now the very definition of "estranged". I see the writing on the wall. She is straight, and cannot be attracted to a woman, and cannot be married to one, and asking her to be something she's not would be just as unfair as asking me to be something I'm not. So we will very likely go our separate ways in the not-too-distant future. I see little hope of finding any reason to stay together. The kids are grown, and we have increasingly little in common.
From her perspective, the marriage always worked well, she was getting what she needed from it, and felt safe and secure. She was married to a man she loved, and felt her life was fulfilled.
From my perspective, because I could never share myself fully, I could never experience true intimacy, which is the one thing I need and crave. We've always had real problems in the bedroom, and I had always blamed that on her, but realized recently it was mainly due to my own difficulties with dysphoria.
