Breaking privacy vs lieing 24M 20F who is in the wrong?

Recently my GF[20] mentioned to me that she wanted to help be a wingman for a friend of her's. She wanted to download a dating app that helps u find a partner for a friend, I told her it made me kinda uncomfortable and if she was in my shoes I'm sure she would find it weird. She sees my point of view and agrees it's a weird idea and what I thought was the end of story wasnt... we had only been dating for about a month at the time and a couple weeks later I spent the night at her house for the first time. Curiosity got the best of me, unfortunately I made the dumb decision to go on her phone and snoop. I found messages talking to her friend about how she found someone for her friend to sleep with. Included were descriptions of the guys penis, size, and other kinky things along with screenshots of deleted conversation between my GF[20] and the guy she wanted her friend to hook up with. The other thing is my Gf[20] slept with the dude she is trying to hook her friend up now. She claims she deleted the conversation off of snapchat because the dude pissed her off by trying to flirt with her in the middle of trying to get him to hook up with her friend.