First let me give you a hug.....I am down that path right now. My wife cheated on me while she was in school. Two affairs! She didnt help around the house and thought it would be more beneficial to see her lovers than to do the housewife thing (she begged me to let her a housewife so i let her....and she sucked at it!).
Have you talked to him about this?
If you have, and no difference....try counseling. If he will not go, i would start gathering your things, little by little and spend some time away from him and leave him a note or something. If you are scared (which it sounds like you are) of him, thats the route i would take.