Something here really jumped out at me: "And now I'm 46 and I still in some ways feel like a child. So, in some small way, maybe that is why I want to go to the dr. by myself."
My father died a couple of years ago, a couple of years after my parents' 50th wedding anniversary. One of the most important things to my mother in their M was that my father "let her grow up." This required a lot of change in their R, a lot of stretching, and I expect a lot of working through some difficult times. I expect this happened in her 40s too. It is something that was very much a part of the deep and lasting love they shared.
So, I urge you to really absorb her wish to grow up and validate it if you get the chance. You might even take a good deal of comfort in it. That is a big part of why she needs space -- to grow up and find herself as a healthy, vibrant, independent, happy woman. OM is perhaps a MEANS to get that space from you, but he is not the END of the space. So, OM is just a tool. (Pun intended.)
Choc, I really still think W is going to come around. And, once she is really invested in working to find a good M with you again, there will be no stopping you. You have GREAT instincts for that act of the play.