I am in a similar situation
I am consistently amazed at how people like this WANT you to love them, be there for them...BUt they are incorrigible...mean, cranky.
My exA is angry with me everyday, and I do not know why. He says the most horrendous things, manipulates our parenting agreements...And he genuinely wonders why he is alone.
He threatens suicide about every three days. His family has a history of that...It is scary, but, I am not the one he is suddenly going to listen to. He wont listen to me, he attacks me. Some one else needs to help him to help himself.
You are not alone. I think you made the right choice for you and your kids.