You and your mother are cooperating in keeping this “dance of anger” going. There is something relieving for both of you in the fights or you wouldn’t keep it up. Meanwhile, make no mistake about it, your little girl is learning that this is the way that mothers and daughters treat each other. I hope that reality will give you extra motivation to make some changes.
My guess is that neither you nor your mother has a healthy self-esteem. She only feels good about herself if she feels morally superior to her ex. You only feel good about yourself when you feel guilty for the fights. Neither position is healthy or helpful.
Clearly there is something that binds the two of you together. You keep trying to be in relationship. You both keep going back for more. But if you and your mom could stop the cycle of anger on your own you would have done so already. I strongly encourage the two of you to get into some family therapy together. Two intelligent women like yourselves can work through your individual and collective pain and can forge a more positive and loving mother-daughter relationship. Do it for yourselves. Do it for your little girl.
I wish you well.