Opinions please.

Okay I know this is going to come across as petty and immature but I'm curious to see other people's views on it. My boyfriend went to a ceilidh for his university athletic society tonight and I jokingly asked him if he'd danced with anyone and he said that three girls he didn't know had asked him to dance at various points throughout the night and he had. Is it wrong for me to be upset over this? I'd be completely okay if they had been friends and he'd known them before hand but to just go with girls who he didn't know who had asked because they were clearly interested makes me a little uncomfortable. What do you think? Am I overreacting?
Edit: I've also just found out that when I offered to come visit for a few hours before he went out since we're on different university campuses and don't get to see each other too often he lied and said he was going out at six when he wasn't going out til nine. I really don't know how to feel just now.