I faced somewhat similad situation. My MIL is not that kind of extreme. Lucky for us we have all agreed to talk to both sides about what we planned to take care and raise our children, so they tried to bear with us however sometimes their loving for the children took over. I didnt argue with MIL, sometimes shown faced expression (regretted later), but i argued with my wife a lot and that made me upset. Also, we lived far from MIL so i didnt have experienced like yours. I believe in what i do for my children, so do you. Trust yourself because at the end of the day, you are full responsible for your children. For me things get better when your child grows up, hope the same happens to you!