It sounds like she's going through something, and unfortunately when this happens the spouse usually becomes the lightning rod for everything that the WAS perceives as wrong in their life. The best thing you can do is detach, leave her be, remove yourself from the equation. She's got to sort this out and it's going to take quite some time, and the loss of the M may very well be part of the fallout of that journey she goes on. There could still be a future R and M, but that's way down the road. For now accept that she's already gone and DB your heart out.
"What is best for my kids is best for me" Amor Fati Link to quotes: https://www.divorcebusting.com/forums/ubbthreads.php?ubb=showflat&Number=2879712