To me it seems like you're with this guy for all the wrong reasons.. You went out with him so he wouldn't kill himself, not because you liked him. You have to ask yourself, what do you get out of this relationship?

He seems very emotionally unstable and you seem very tired. I think you should leave him. If he says he is going to kill himself, well.. I think that you should leave that to his friends and family in real life who can give him proper support and possibly into therapy for his problems.

Good luck!