This is not a person acting like 4 year old. This a woman/child deeply harmed. You need not fix her, talk to her, or deal with nor comfort her. She has a great deal of hurt that has grown a viscious tumor of hate inside her. This is her battle, not yours. Sheild yourself as best you can, and let her actions and words roll off you with the wisdom you have inside you and gain from these boards.

On the practical side, legal issues are in question, thus protect yourself and your husband legally. Legally is so much easier than emotionally. One peice of advice, any word about her mother quickly lowers you to a level you most likely do not want to be in. You being hurt or not, attacked or not, you have a choice to remain in a better place than to attack back.