Question about orgasming without cum

Last night I was riding my boyfriend and I knew he was about to cum and he told me he was about to cum...and all of a sudden he orgasmed...but a few seconds later he goes "whoa, I didn't cum." I was like "what?" and he said he felt it about to happen and at the last second all the pressure from the angle I was in kind of closed off the event of cumming, but he still felt an orgasm. Has this ever happened to anyone else??

And yes, I'm gay.

orgasm without cum? is that even possible?

thats like saying "drowning without water", isn't it?