My Girlfriend cheated twice[cheating]

As far as I know my girlfriend has cheated twice. The first time was when we first started dating. She was with friends at a party and some guy asked her if she was single. She said no and he said that was cool or whatever but after a little while he started hitting on her and asked if she was open to cheating on me. She told me she said no but I found out later she was texting him on snapchat. They had been sexting and sending nudes back and forth for a little while.

The second time doesn’t really count because we were on break. We got into a fight and decided to take a break for a little while. When we got back together the first thing she asked was if I had been with anyone else. I told her no(I had been) and she said no too. I knew it was a lie but I didn’t push. After a little while we were hanging out together and she left to do something. I grabbed her phone and went through it and found screenshots of her sexting with multiple guys and a video of her getting fucked by someone she works with