"Im scared bf will kill himself if we break up"?

When i first met him i didnt know he did drugs and drank so much alcohol because he is always much more happy around me. I heard he was really bad before i met him, and i made him start to act better.

But he is jealous and controlling and i dont know how much of that i can handle all my life. But i love him a lot. Sometimes i think.of leaving him but he has said before that he doest know what he would do without me. We have broken up for very short amounts of time, and during those times he was a mess. Doing drugs and drinking alot. I am scared that if i left him he might accidentally or on purpose kill himself. That makes me so sad and upset because i do love him but i dont think he.is the one for me. But i dont want him to die because i still care alot about him.