I picked up on a lot of similarities, which inspired me to post all that!
You already know what you're dealing with and are planning ahead and getting support. I didn't.
What really helped me see what was going on, and to break contact (took him the best part of a year to take the hint, mind) was getting counselling.
The guilt is the worst. I told my ex when we split that I was sick of cleaning up after an overgrown teenager but it still took me a while to stop playing my part in that. I don't think I'd have got there without therapy.