Possible? Sort of. In the world of sex you will have some wins, ties and losses. I wouldn't put this in the L column, but unless he has some physiological issues which prohibit him from ejaculating, or is a Tantric sex guru, he probably didn't orgasm. When most people say they are "finished" it implies they climaxed (men, that is). Unfortunately, women are often finished when they realize their men are never going to get them there or Girls is on.
This being your first time perhaps, and I do mean perhaps, your man felt like you gave a valiant effort and it felt good, but it wasn't going to result in ejaculation. C'est la blowjob. Keep in mind, you didn't tell me if the guy is inexperienced too. I'd say 75+% of the time guys don't come from blowjobs because of their own emotions not because of their partners lack of skills or commitment.
I say move on. Put it behind you - you have plenty more head ahead (if you wish).head? Go back into "the gym" and get your serve right. Only then will you be aces.
I had a friend who dated a guy who just ejaculated very very little sperm. There was something there but a lot of times she said she wouldn't have known he finished except he said so. Yet i know the guy and he was being honest about it - he wasn't one to be nice about things and they had a great sex life (the only thing good but i digress). I do remember her being concerned if the relationship went anywhere that he wouldn't be able to get her pregnant because of the little ejaculate but that didn't end up becoming an issue. So it could just be how he is. If you like the guy I say keep trying and see where it goes.
It's possible. It's not possible for him to finish without ejaculating, but it IS possible that what with all the other fluids in your mouth (saliva, precum, etc) you didn't notice the cum.