Too Controlling?

I go to school with a girl who is in a relationship, yet promiscuous. I’ve given her a few rides to school (she lives close to me), but we are simply classmates and don’t associate with each other outside of school. My bf recently blew up on me because he’s scared that her ‘thottiness’ will rub off on me. He doesn’t believe that I should be associating with a person like her and stated that he’s tired of thinking for me... WTF.!

I feel like I tell him everything to a fault then I regret doing so afterwards.

Opinions? Please don’t hold back.