Guilt is not the correct emotion here. You are not guilty in any way. You tried to save a drowning man. You gave him a life preserver. But he sank again, regardless. You broke up with him as to not let him pull you down with him. Self preservation. He was drowning before you, and he is drowning after your help. It is not your fault in any way.

What you are feeling is empathy. Your heart breaks for this guy. I have felt that, too. You just have to keep him in your prayers and wish the best for him. But he is his own worst enemy, and it has nothing to do with you.