I made a list of things I could do to improve things, in light of your list. Then I erased it, because I realized it all came down to one thing:
I have to let go.
For my sanity and my marriage I have to just let it go. I can't keep it all in my head and try to hold everything together. I can't worry about W and her boss, or her family, or her job.
(The only fuzzy area, where I need to exert some input is in raising my boys.)
Honestly, I'm not sure I can detach this much. But that's the answer.