Bleeding during/after sex

This past weekend I went to visit my boyfriend who I just recently started getting serious with. I was happy that my period had ended 3 days early as we hadn't seen eachother in 3 weeks. While we we having sex we noticed blood on his penis and between my legs. He is a bigger guy and I do enjoy sex to be slightly more aggressive, but this isn't something that's ever happened before. There was no pain or discomfort before or after. It was a pretty minimal amount of blood, and was slightly less the next day when we had sex again.