Like everyone else said, there is absolutely NO reason to have someone like this in your life. Pack up all his stuff and take it to the police or sherriffs department for him to pick up. Or, since you are a lawyer, I'm sure you have lawyer friends whose office you could take it to for him to pick it up ALONG with a restraining order. I'm all for you getting some sort of personal defense weapon, whether it be pepper spray, a dog, a tazer, or a gun. However, if you DO get a gun, get a short barreled shotgun and load it with 00 buckshot and be DAMN SURE that you would be able to use it if you had to.
Another reason to get the restraining order is to protect yourself LEGALLY. Since you are a lawyer I'm sure you already know that but if you have the thing and he DOES come after you it would be self defense without question.
Bottom line is get him as far out or your life as possible before he DOES kill you.