You have only known this guy three months. Trust me, it wasn't anything you did that caused any of this.
I know what it's like to try to walk away when you feel like you care about the person, and particularly when you feel in some way responsible for his well-being. Not to mention that he owes you money, so you have a material investment.
My suggestion is, too, that you cut your losses. Consider it a lesson learned (albeit an expensive one), and do NOT see him again. Believe me, he will find some other woman willing to clean up after his mistakes, and use her the same way he has you.
In only three months you cannot possibly know whether anything he has told you is true. Some of the most charming people in the world are sociopaths who know how to get people to love them and think they are "special". Ted Bundy was EXTREMELY charming.
Obviously, I'm not suggesting this guy is a serial killer, but he may well be a serial "user" who latches onto women, makes them feel incredibly special, and takes and takes until they wise up.
Let someone else deal with this train-wreck of a man. It's personally embarrassing to feel used (I know, I've been there), but it's better than allowing yourself to continue to be victimized.