If you feel like you need to arm yourself to leave your apartment-honey it is time to call in the police. Like you said--they will give him a place to stay. He'll even get 3 meals a day. He is not your problem and you do not want to get into some sort of fight with this fool that will make YOU wind up in the place with 3 meals a day.
He will be back. You let him in once so he will try again. Having the police tell him if he comes back they will arrest him for disorderly conduct (or something else) may give him pause.
stbxah pulled the suicide card many times. He cares to much about himself to kill himself. Sounds harsh--but true.