Hi molly
Well, possibly it was always ever only going to be a one night thing. Possibly not.
From my perspective, if you jump into bed with someone quickly, it lessens the chance of building a relationship with someone. It's got to be either an amazing mental spark with someone, or amazing, mind-blowing sex with someone, for a man to want to see them again after one date, which ended in sex.
I had a great date the other night. Now I don't know if I want to see her again. Distance, flakiness, and a few annoying things she's said.
If I'd gone to bed with her that night, there's actually a smaller chance I'd want to see her again.
I'm not saying I'd want to see her again for the challenge of getting her into bed, or anything. I want to have a relationship.
But if I sleep with her very quickly, part of my lizard brain will lose interest in her, so there had better be an emotional connection which is strong enough to compensate for that.
This is not behaviour I choose, of course. It's subconscious.
Have you tried sending him a message? Nothing clingy, or overly sweet - just something funny, acknowledging the awkwardness maybe, and seeing if he fancies a second date?
That's worked on me before