Last I heard you were never going to contact her again and that the only contact you would have was if it concerned your son.
Have you two ever discussed getting professional therapy? Why do you let her wheel you in only to spit you out again? Start your healing by reading the book "Codependent No More" by Melody Beatie you are sorefully afflicted. Once you realize what keeps you stagnated in this unhealthy pull in / push away dynamic with your screwed up ex, you'll be able to overcome and get yourself emotionally unaddicted to her.
I truly feel sorry for your child(ren) more than anyone.
Get the book and call your local mental health hotline for a referral to speak to psychologist. Your son deserves a parent who is happy and well adjusted.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion