Bless you for posting.

Something that many years later is causing the significant problems you describe should be treated by a professional and not by a partner. That is the goal for now in my opinion. She can benefit from professional help.

Therefore I like travelinglady's idea of you seeing a counselor yourself, so as to find out how best to speak with her and encourage her to find a counselor, to deal with your own feelings about the situation, and to set an example for her.