I wish my WAS gave me an ultimatum. She only ever said a long time ago ... "If you cheat on me I'll leave" and that was a casual conversation, not even a serious threat (don't remember what we were talking about).
The closest she came to telling me she wanted a D was when I asked her if she cared about me and why she was so distant, and she said "I'm here because of [oldest daughter]" - that really scared me but she wouldn't elaborate further than that.
I wish she had told me a while ago; "Hey if you don't shape up or don't do this, or if you don't stop travelling I'm leaving" that would have been a much better conversation to have. She admits that she didn't communicate things well, although the other day exasperated she told me "You wanted me to spell it out like this .. {waves hands in front of me}"
She's in a total emotional disarray, a month ago she seemed more stable, I see her regressing. Not sure why.