To take care of yourself, the best and quickest solution is to leave this guy alone, ASAP.
You two havent even dated for that long but all I read was a lot of fights, on and off's, communication via emails, and that he "cussed" you out when you brought up the subject of seeing others (which easily could've led to an exclusivity talk), then he left you high and dry over concert tickets, on top of all of that, you don't trust him and thinks he's seeing another woman, you had to find a friend to do the detective work for you.
You say you know he cares about you? I've yet to see which part and how. When you want to talk about your feelings, he shuts you out emotionally.
This isnt about you having trust issues, that's because he never did anything good to deserve your trust to begin with. Kick him to the curb and tell him to have a nice life without you.