I stayed through my STBX's episodes. I begged him to go to counseling and stay on his meds. I relate it to addictions more than cancer. He had to want to help himself more than I wanted him to help himself, and he just didn't. This is probably why I say so often that I had plenty of reasons to leave before the cheating, but that was the straw that broke the camel's back.
I feel for you BeautifulEmpty, and I'm actually thinking now he is in a very tough spot as almost every last one of our mutual friends have abandoned him, and he has limited family already. He still has MOW, but of course we all like to predict how long that will last, which is not that long (especially given he already cheated on her since we separated).
Like addictions, I really hope one of these days the consequences are bad enough for him that he realizes he needs help.. I hope he does this for the kids because after the years of torture, I'm done with him for good. I'm just not strong enough to put up with that anymore. The emotional and some physical abuse was far more than anyone should have to take.. But you give a lot of hope to people have truly "remorseful" bipolar spouses who would really take the steps to get healthy..
How are you doing WaryOptimist? How's your daughter?