Thank you again, sandi2. I took your advice, impulsively, and left the dinner fixins half done, for the girls to finish cooking themselves, and saw a good movie (Monica Z, should it make it over there). I did not inform anyone about doing this - kind of fun, actually.
Why is doing this enjoying myself - beyond its being strong and independent - good to do? I have the option of going back to the States, partly for work, partly for EE - which would lighten the psychological burden on my W also, plus I have more fun in California than here (there is simply more to do there).
One issue is when to inform my MIL that W and I are having serious problems. I don't want her pressuring W, as this probably would complicate things. In any case, when I do inform her, I think it would be appropriate to no longer stay at her house, where she so kindly has put me up (and up with me) for 15 years.
M58, xW54 S22, D18 M 1984, D 2016 Living a new life.