am I in the wrong

I was watching a movie with my boyfriend and I glanced over at him texting, I noticed it was some random girl named Brooklyn..he's never ever mentioned having a friend named Brooklyn and I've never seen him text her before in the whole time we have been dating so even i know it's not just one of his female friends. I asked him who she was and he read out a couple of messages they had exchanged..to keep me happy I guess, anyway I grabbed my keys and drove to Coles pretty upset to be honest and he turned all shitty with me for making a deal out of it..now he's stormed out of the house on some walk somewhere with a beer and won't tell me where he is..