Hi Robyn,
Have you been to AlAnon? You need help and support to deal with this, and they deal with this ALL the time. Counseling would be a huge help.
And to help you feel better if you need to cut her out for good - that's OK!! Family is not just blood. It takes more than biology to be a parent. It takes love, care, and respect. You are NOT her mother or her caretaker. She has to take care of herself. It is possible for a parent to destroy the relationship with their child - it takes a LOT of work, but it happens. My mother did it to me. I speak to her maybe 5 times a year, usually when she wants to brag on herself. I am polite, but that is it. I am very glad I live 1000 miles away. But even if I lived in the same area, I would not visit her more. She is not a healthy person to be around or to have a relationship with. I would never leave my son alone with her.
So give yourself permission to do what you have to do to protect your family (spouse/children). If that means not having any kind of relationship with her, then that is what has to be done. Go to AA, get some support, some counseling. Find out what you can about being kept in the loop as far as her attending meetings, etc.
Good luck and HUGS!