I don't know why guys seem to do that. They will keep you hanging by a thread if you let them. Nothing personal guys. But I think women are more into romance and being together, where guys just do their own thing. As the mood strikes them.
It does sound like he is trying to make you jealous. Quit being so avaliable to him, let him come to you. See if that works. Try it for awhile. Men want to do the persueing, though he sounds like he is playing hard to get. I would try to occupy your mind, forget about him for awhile. When he comes back, and he will, make it on your terms. Don't make him top priority. I bet he will be calling you more. If that is what you want. Even as just a friend.
I hope that this helps you some. He is taking control of the relationship by trying to make you jealous. Don't let him do that. But if that is the case, it shows that he still cares. He wants to get a reaction out of you. Don't let him.