Ask him if he wants to be a rebound boyfriend, or a long-term boyfriend. If it's the latter, he needs to cool it for a while and give you time.

Ooo, I had the same thing happen when I got divorced from my first husband. Two of my very good friends who were guys, and whom I had known before even meeting first husband, started coming on to me. It was a HUGE DRAG. One of them suddenly kissed me and I slapped him as a reflex and that friendship was never the same.

Tell him he just has to wait a little longer!