I am going to sound harsh here, but you are not protecting your children, and you are in fact, contributing to the harm that is being done to them by their mother. You enable her and you still want her love and affection, when your children are screaming out for help from you to support them in their plight with their mom. You are neglecting your own children's needs, and you are contributing to the abuse that their mother inflicts upon them by enabling her. It is very disturbing at this point.

Take the kids and give them to other family members to watch over because they are crying out for someone to take care of them better.