Ginger, I think it's fairly easy to decide if someone put a lot of effort into saving their M before they gave up.
Did they ask their spouse for conversations? Did they bring up their complaints in a calm and non-blaming manner? Did they go to IC to help them figure out if their expectations were reasonable? Did they ask their S to go to MC? Did they take classes, attend weekend seminars, keep asking their S to go to counseling?
I did this for years. I finally told WH some years ago that I was worried about the future of our R if we didn't get help to communicate. He has later told me that it was at that moment, when I 'threatened D', as he calls it, that he started to withdraw.
He eventually got into an A and now lives with his mistress. I'm pretty sure that the pattern will repeat, I was not his first round on that carousel.
I'm working hard to avoid repeating any of the patterns that I saw were destructive in that M, and find out where they originate from.
M 16 yrs, WH62, P54 3 adult blended kids EA 11/13, BD1 6/14 PA fall 14, BD2 2/15 Piecing 2015, BD3 12/15 Separated 4/16 WH moved OW in 5/16 Divorced 6/15/17