Wow, you have been with this a$$hole for EIGHT years?! I likely would have done something to send myself to jail if I lived with him that long. What most of us don't realize when we are in this type of situation is that the longer we procrastinate, the longer we do NOTHING to take care of ourselves, the longer we IGNORE our needs, the greater the opportunity we give to that other person and/or his actions to seriously hurt us in one way or another.
You are likely waiting for something to provide you the momentum to GET OUT. The situation you describe sounds like you may be so affected and depressed by the way you are treated that you have even LESS motivation to act than normal. Many of us have waited until our very lives were in danger from either the other person or from the mental illnesses that develop from living with those kind of people.
Sometimes all it takes is someone telling you to get out. This is why it is important for you to have real, live, social supports in your community. Do you have family and/or friends close by?
You need to get away from this person, physically. It is a VERY unhealthy situation you are keeping yourself in. It is NOT a matter of "leaving" him or not. It is a matter of taking care of YOU. If he were a wild lion in the jungle and you were in danger of being eaten by it, would you say, "Oh, I'm not sure if I should leave this lion"? No. You would get the #$@! away from it.