Who knows? At that age all of you are just walking hormones with emotion directing you this way and that!
You can be in control. If he broke it off with you, tell him what is going on? Its over! You don't have the time nor inclination to rehash or dance over his regrets. You have entirely too much to do and frankly, he did you a favor! Now you are free to concentrate on your future goals without him manipulating your every move. Feel the freedom and enjoy it!
BTW, when he decides to hook up with someone else to piss you off, don't let it get to you. He had it good and decided it wasn't good enough. He probably thought the grass was greener somewhere else and found that she (the other grass) wasn't interested. Now he's back and you have become sloppy seconds.