Dating while pregnant?

So I broke it off with the father of my child over what was explained in another post the other day (innapropriate friendships, crossing that line) We've been off and on actually for a few months and recently our "on" times never lasted more than a few weeks. Over the past few weeks, a coworker has been extremely sweet, sending flowers and so on. He has been hinting around at trying for the next level, but I shut him down. I do enjoy the attention however but find it weird dating while pregnant, lol. Also, it is too soon, I don't want to rebound date. This guy is the total package though, sweet, educated, considerate, hard working... And another thing I do kind of like him. When is it considered "appropriate" to start dating again?