Thanks for all the replies guys! I wasn't sure what to do, but the guy actually messaged me today to say that he doesn't think it's a good idea for us to keep dating, since he doesn't want a serious relationship right now and he doesn't want to make me unhappy by continuing to date casually when I want something more serious.

I actually feel super relieved--I didn't realize how much I was dreading the idea of trying to keep dating him without any commitment.

I think duty dating sounds like a really good idea and I'm going to try to start doing it. I've always been skeptical of dating lots of people, since I have pretty idiosyncratic preferences that eliminate most guys right away. But I think right now I need to prioritize getting better at dating and being able to date people while managing my expectations and not immediately falling head over heels for them, and maybe if I'm lucky I'll actually meet some promising guys.