"...a sullen lump that refused to even make small talk..."

Aka, a teenager.

"...knocked on the door to make sure he was okay. I apologized and he called me a bitch and slammed the door in my face..."

If I read my annoying teenagers right, he also felt as if she was guilt tripping him. She probably wasn't, but if someone is in X-tra Sensitive Land, it will often feel that way anyway.

Me, I *do* think 'forcing' an apology out of a sullen jerk is enough. If it'd've been me, I'd've taken him off to ice cream a couple times, and otherwise listened to the radio/podcasts while carpooling.

Anyway, all that aside: at the current moment, dooo not marry this dude, you are not the right mom for a bunch of carping half-communicative sad people. Maybe keep dating him and keep distance until everyone gains some more sanity points.