saying bad things to your baby

I have mil saying back things about me in front of my children. End up I move out. Staying at my own nest without her. Now she is staying alone. That's good. How can she do this. Very unhealthy for children. My hubby knows. Actually I ran out of home twice then decided to move out to have our own nest. Cannot stand her. If your mil has a own home then ask her move back if not happy otherwise ask her to keep her mouth shut!!!