How do you get rid of the negative people in your life if they need you?

So recently I decided I would cut all of the negative out of my life which included a few people that I’ve been close to for years. This was a pretty huge thing for me but it needed to be done but it didn’t work out well. When I told my ex and bestfriend (same person) that I was done with my past he didn’t take it well. A week or so later he attempted suicide, it was BAD. So I told him I wouldn’t leave him feeling like he has no one left again but all he really does is mess with my mind and my emotions, how am I supposed to begin to fix this?