Anne,
Common wisdom is that people need to have a period to transition from one relationship before jumping into another one. There is that period of closure, of resolution, of grieving, of healing, of being independent and self discovery before being emotionally healthy enough to start another relationship.
My guess is that he is still in a state of emotional turmoil and not really ready as he thought he is for you. I can relate for I thought I was emotionally ready right after my divorce but I really needed that space afterwards before finding someone else despite what I thought.
What should you do? If I told you that you should move on, I doubt that you really want to hear that as advice.
Mark