The mother in law sounds very overbearing and toxic. Would it be possible for you and your wife to get into couples counselling? A counselor may be able to help you and your wife set boundaries with your mother in law. If your wife is not willing to do that, you'll have to decide if you can deal with that type of toxic relationship in your life, or if you want to divorce and move on. I wish you all the best regardless of what you decide.