Would you be upset if your bf had you hang out with a chick he made out with in the past and didn’t tell you?

Invited me to go to an amusement park with his friend and friends gf, and I paid for my bf and my ticket. Finds out he made out with that chick a while back and didn’t tell me until 7 months later. I feel like an idiot being the only clueless one between my bf and that girl, and I tried to make Convo with her the whole night but she was cold and did not respond to my small talk and I was unsure why. Also icky bc it’s the gf of one of his closest friends, and even if they were not dating before, it would be odd no? We are all 23, out of college. I am upset bc this is not the first time he’s withheld info from me. I am disgusted lol. Plz give your opinions / advice, ty .