I agree with Christina. God for bid you marry him and then have children, you're going to wish five years from now that you ran away and never looked back. Even if he isn't sleeping with his mom, I do agree that there is some sickness going on there. I also think Keylost is right that you're getting your head messed with not only by his mom, but by him too. They see what they are doing is bothering you a lot and some people mess with other peoples heads just for the thrill of it. That might be what your fiance is like, full of drama and mind games just for the fun of it and he probably gets that from his mom. They get a kick out of upsetting people and even if you're not saying anything, they can tell that they you are getting to you good. You are giving them exactly what they want by being upset and bothered. Don't let them play you so easily by giving them the reaction that they want. But in the meantime, I would be making an exit plan, please get out now or you are going to regret it in the future. These are not nice or healthy people. We don't really truly know our significant others until stuff like this pops up.