A surprise that almost broke us up

So my boyfriends and I were arguing and a girl names pop up on his phone. So I spazzed out and I cussed him out. I kept asking who she was and shit. But he wouldn't tell me. But he after all of the yelling and words he told me it was to get tickets for a concert that was all sold. I feel bad. But how was I suppose to know. He always get defensive when another male text me. Idk. Plus he was out partying all night with his friends I thought he had got a girls number. Smh now my day is ruined so is his.