Glad you were able to remove this person from your life. A good friend of mine had a similar episode. Finally divorced and remarried. Sure he loved his first, was his big, first love which can be hard to erase...
Before my first marriage I have to fess up to having done similar. Over the years in fact, now an old fart; the endless stories I've heard, the number of people who were in similar situations is mind boggling!!!
Perhaps most important, at least from my tiny perspective re your experience: Life is soooo weird isn't it? I mean just the stuff that will happen to us is enough writing material for a long time haha!
No, I'm not belittling in any way your very trying experience. I can only hope that you've found some daylight since those trying times now past.
Thanks for letting us in.