After quarreling with her mother-in-law, she began to be cold and violent. What should I do?

It's simple. First, you can't give up, or you will be bullied in the future. But not too strong.

So, let's just pretend we never had a fight and do whatever we want. Let your mother-in-law think that you are: the kind of heartless person. Slowly, she will let you go.