It's good he ended it before he or you got further attached to each-other, odd you're under 18 and somebody would have the maturity to be able to do that though. Good guy though, was honest to you about it, even if it hurts ya.
It's good that he put a stop to it. Granted, it could be considered strange since this kind of thing does not happen often. Usually, people just keep using the other person until they end up caught. It's a shame he couldn't seek a therapist and work it out so he could still be with you. Granted, he could always come back if he got his head straight.