When it comes to my mother-in-law, I think she wants more from her son than she should.
Can you tell me how she asks too much?
My MIL is a powerful woman and she wants to control my partner and me.
You should be careful when interfering with your partner's parental relationship. If you have a problem, you should talk to your partner about it and take it from there. They might be able to address the issue in a way that won't cause as many problems.
One day I'll prove that my MIL is the one in the wrong.
As of now letting your partner deal with their mom is the best solution as getting yourself involved could make the interference worse and possibly cause a rift between you and your partner. They probably know how to deal with their mother in a way that will yield better results.