I think you will have to evict him. He's been there for 7 years and has clothes there and gets his mail there so the police can't do anything because that is now his home to.

You need to take back your apartment that is your "safe haven" don't let him have it fight for it. Yes it will be frustrating but if you don't do it then you loose your safe haven and he gets to keep being a jerk.

Good luck.