Wow. I am so sorry you had to go through that. It is hell on earth thats for sure. I think where I struggle the most is with my responses. And Steve has told me over and over only answer y/n questions, informative texts dont need responses. Only discuss daughter. But I tend to be too nice. Not make clear boundaries. I have been SO afraid of making him mad because as soon as he is mad he throws divorce and custody issues at me, but I am feeling no longer afraid of that. He is doing wrong, I have every right to set boundaries, and if he has a problem with my boundaries then he can do what he needs to do.
I just need to stick to them. I constantly let things go because I felt like if I wasnt the level headed one, then the situation would just go completely south. But it isnt my job to clean up his messes.