Sometimes it is a great experience if you can easily fall in love. Then a month or few weeks later. One of the party gets bored for lack of a better word. I found that giving in too early. (I.E. saying I love you everyday) can actually remove the sincerity of it. If you hold out on your feelings. Playing a little hard to get. It attracts greater interest then just giving yourself away.
It sounds to me that he wants to keep chasing whatever is easiest and he does not mean what he says. That's sad but if he does not know what good thing hes missing out on. Perhaps try to tell him you have a friend that wants to take you out. Use his jealously against him. Do not flat out saying your seeing another guy. Just pretend like you are and when you talk about it keep it short to make him wonder.
Either he does care and will come back to you. Or he is just chasing woman after woman in that case you really do not need him.