Well, I managed to do it. I actually confronted my trouble guy, and he is gone, for good this time. He said he didn't want to stay here anymore because he didn't trust me (as in to not look at his phone), and I said he was hardly innocent, with his folder of nasty photos of girls he's taken personally or gotten them to send him, his lewd convos, and telling the one girl he knows I'm the most insecure about how amazing she is, and asking her when they can hook up. So yeah, him leaving was best.
We had agreed we shouldn't be enemies. But in a funny twist of events, something happened that he wasn't happy with, he blames me for it (which I'm inadvertently involved, but I had no idea that said event would happen) but he has no proof I am in any way involved, so I'm claiming ignorance, and hoping things will sort themselves out. If I really wanted to rain down hell on him, I know how I would do it.
Anyhow. As sad and frustrating as everything is, I know deep down it's for the best. I just got to get my head right after everything that's been screwed around with it.
Making progress!