What I found on her phone[Cuckold Perspective]

So me and my GF (25) have been role playing and sexting and about her cucking me and cheating on me for some time now. One night I saw that her phone was out and unlocked, I couldn’t help but want to go through it so I went to her Snapchat messages and noticed she was messaging a few guys. One that stood out to me was from her ex. I opened the recent unopened message from him and I nearly instantly started getting hard. He was messaging her about cuming deep inside her and how hard he wanted to fuck her. She was nearly worshiping him. As I scrolled up i saw she was sending him pictures in her panties. I also saw he sent her a dick picture in the mirror and couldn’t help but notice how much bigger it is than mine. I kept reading the dirty talk between them and had to take the phone to the bathroom and jerk off. I nearly came instantly with how worked up I was. After I came into the toilet I was so humiliated with myself. I never told her about me finding the messages and think about it a lot and jerk off to the thought of her fucking her ex behind my back.