My attorney (who is also a co-worker and friend) told me that I cannot simply throw my AH out even if I file for divorce unless he becomes physically abusive, destroys property or threatens me or our son with physical harm. Even then I would have to get a restraining order to force him to move. In most states a primary residence purchased during a marriage has both names on the deed, that is why you can't just "throw him out". Now if you go through a divorce and the court awards you the house then he must leave.
I have personal experience with this issue, my parents divorced and my father refused to believe my mom was going through with it and would not move out (he is not an A just a big jerk). The judge had to tell him to move out at the final hearing......in many state's the term "a man's home is his castle" is alive and well (Terry's experience with the police is pretty typical). Those who can get their A to leave are lucky IMO.