Girlfriends messages to ex

My girlfriend and I have dated for almost a year, but we have been friends for a while before. I remember her telling me stories when we were just friends about all of her sexual encounters, it didn’t turn me on then nearly as much as it does now. I remember her telling me how she measured her exes dick with a ruler and it was 8 inches (mine is 5). I remember her telling me about how she had her first college hookup, and how his dick was even bigger than her exes. And now we are dating. I look back and miss how she used to tell me about her slutty past, and now all I have is looking back at our old chats at the faces of her previous partners with bigger dicks than me. Sometimes I wake up earlier than her in the morning and look at conversations she has with her friends about her past hook ups. Now that we go to the same college I’m going to try to get her to cheat on me. I just can’t get over the thought of watching her face as she is feeling a bigger man inside her.