He pursued you to have an affair with you while he is married. Say he gets divorced to be with you. You'll always have in your mind how he was quick and ready to cheat. He would do that to you, too.

If that doesn't bother you, you could tell him you have feelings for him and hope he will divorce his wife and be with you. Then all you can do is wait and see if that happens.

Or you could just leave him alone and find someone available and honorable.