I understand how that might bother you. But I actually realize there are amicable divorces in this world. I don't know the reason for their D, but I have seen ex's become friends after, because they actually realized they were better off that way.
I assume you know more behind that situation and if it is truly something to be concerned about, or it just makes you a little jealous. Which is a very normal feeling.
he sounds like a wonderful guy, and you sound very happy, actually. Scared, but happy.