Leander,
Wow!! You are where my husband was about 4 or 5 years ago. He went through what I called a midlife crises. He was about the same age as you and pretty much said all of those same things to me. It hit me like a ton of bricks, because for me it had come out of nowhere, although for him it was something that he had felt for a long time.
Of course I tried to talk him out of it and to just keep on keeping on, but he was determined. First, he made the decision to stop going to meetings. It was hard for me at first but as a friend told me "The more familiar something is, the more acceptable it becomes". So I got used to that.
Then he decided that we should separate so he could experience life on his own and find out who he was and all of that. So, because we have two kids together, I told him that he had one year to figure it out and if after one year he still wasn't sure I was going to divorce him and move back to our hometown, which is clear across the U.S. If we wouldn't have had kids, I don't know if I would have given him that time though.
Well, it was the worst year of my life, but I wouldn't change what happened for anything. During that year we stayed civil "for the kids". Which was really hard for me because I wanted to rip his eyes out. Also during that year I tried to see things from his perspective and understand how he was feeling. And just because I didn't feel the same way didn't mean that he was wrong for feeling the way he did.
I also got a taste of what life would be like without him and decided that I wanted to be with him more than anything. Oddly enough, my husband is a musician and wanted to be in a band also but I always made him feel stupid for wanting that. But while we were separated he formed a band and they've been together ever since. And I've since discovered that he is a much better husband and father when he is allowed to follow his dreams and passions. And I needed to find my own passion and stop trying to control him and his feelings and decisions.
We did have a lot of marriage counseling during our separation. And we both made a lot of changes in our personalities for the better. I became less controlling and he became more tolerant. Which helped a lot. And yesterday we celebrated our 14 year wedding anniversary. We have never been happier.
I don't know where your journey is going to take you but I just wanted to share my experience from the other side.
Shimmer