We have been dating for 5 months now, and about a month ago we discussed the how the relationship was going. We both agreed we would be exclusive with each other and make a dedicated effort to make the relationship grow. Today I found some recent text messages on my girlfriend's cell phone flirting with another guy. A couple of them indicated he wanted to invite her to stay over. She did flirt back, but did not respond with anything incriminating. Some of the flirting included phrases she uses with me, which really upset me. I didn't want to confront her about it at the time because I wanted me time to rationally think this through. Does anyone have suggestions on how I can confront her about this situation? I don't want to be snooping around in her phone and constantly be worried that she is cheating on me.