The most important relationship you have is with your wife. You are a good guy to allow your MIL to stay with you and have been respectful. I feel it is up to your wife to resolve the situation. It sounds like you have a good marriage and you need to preserve it at all cost. If you haven't expressed your feelings to your wife in a loving way, you need to and help her resolve it. It's her Mother not yours. I can't relate because I've had 2 GREAT MILs. Good luck.