I know she's extremely mentally ill, mean and selfish and cruel, yet I expect her to change and on top of this insanity I keep holding on to a belief she will one day change and be a nice person.
Do you have people in your life that are mentally sound that you can surround yourself with? I think it might help to be around people that are not like this... .play in that world for awhile and your ex will become a smaller and smaller issue. Right now, you have to interact with her so much because of your son, it is consuming. Try and balance with some "healthy realtionships" if you can... .
Hoping it will help you to see more of the world you want to live in rather than the one that is trying to suck you back in... .
Hope you can find some support, having children with exBPD has got to make it 1,000x more difficult.
hang in there,
Bunny