Physical & Emotional Abuse Support Group
Abuse is a general term for the treatment of someone that causes some kind of harm (to the abused person, to the abusers themselves, or to someone else) that is unlawful or wrongful. No one deserves abuse, period. Abuse can be emotional, physical, or sexual.
Be very professional about the hand off when you get visitation. Don't return to the friendlier ways of your marriage. Just end the contact. You have the perfect reason. You are divorced. If your son asks, don't tell him the details, but do point out that you and his Dad are not divorced for no reason. Then, say no more.
I wish you well with your son. He is lucky to have such a thoughtful Mom who cares for him so much.