Ooh, I like that!!I might send a carefully worded e-mail mentioning the following:
"...explaining that as the grown up sometimes you need to remember that kids make mistakes but they count on those they care about to still care about them regardless" and "...ds thinks you're great and really would like to continue having a good relationship with you", maybe work hurt feelings in there somewhere.
But I would stop short of demanding or even asking for an apology. He isn't sorry, so what is the point? I would simply make a statement of fact. "he is a kid, kids do things they shouldn't, they need to know that they are still loved/cared about, his feelings are really hurt", and leave it at that.
FWIW, I could see my husband getting all pissy over something like that also and my husband hardly ever admits to being wrong in situations like that. Getting him to admit it or apologize just makes it worse. It is better to state your views on the topic and move on. Give him time and space to process it. He may not but he may. Who knows.