I'll just say this right now and I hope I don't hurt anyone:

Suicide is not something someone "tries" and people who commit suicide do NOT use it as a tactic to control someone else. It is a lonely, hopeless state that you don't leave. If he's lived this long (especially if you're paying his way) he is not going to kill himself. He obviously thinks too highly of himself to do that.

And if he does? I'm sorry, but so what? If he truly is going to do it, would you rather:

He commits suicide in your home?

or

He does it and you never, ever find out because that crazy dude is out of your world?

Think about it. I hope you make the right decision. My fiancé has crossed some lines with me but he's never gone to abuse or manipulation. I just don't understand that at all.