I understand your situation and would suggest the following two books, both written by Rhonda Findling:

1. The Commitment Cure: What to Do When You Fall for an Ambivalent Man; and,

2. Don't Call That Man.

I found both to be rather helpful and supplied reasoning as to why one can become attached to an ambivalent man, especially when sex is involved. You may find them in your library, and if not the price is cheaper at Amazon.com.

I know it is painful, he is not quality material, and please do not contact him again for I feel he will only string you along for his selfish reasons and you will be hurt again. Also, you need to heal, thus stopping all contact will enable the healing, this includes emails, phone calls, letters, google searches, etc. If he contacts you, it is only b/c he wants to fill a void for a short time, do not become his puppet, or you will find yourself devalued in his eyes and then he wins. Yes, this hurts, but you must stop the contact and I promise it will benefit you, not immediately, but it will. Do not live in limbo for this bimbo of a man!