blood during sex

so I thought my period was over and so my boyfriend and I decided to have sex. well he stopped randomly and said there was blood and kind of freaked out a bit... what are your opinions on this? it's not that I care about not having period sex it's just the way he went about it. he wasn't rude or anything just was like "grab a towel, I need to go to the bathroom" like freaked out and then didn't talk about it after. it was like two days ago so I'm not upset like I was when it happened but I just want some opinions on his behavior.