He cheated on me

I was going through his gallery to delete ugly pictures of myself he had screenshot while he was busy helping my mom build a table. I really wasn’t looking for anything at all to prove his infidelity. He had told me he stopped talking to a girl I knew that he was trying to hit on while we were on a long break. As I scrolled through his gallery, I saw one picture in particular. A picture of another picture taken from his other phone. It was her. I looked for his other phone which he only “uses for music” and I found more pictures of her. I went to his messages but there was nothing there. Out of instinct, I pressed a random message, and a message was written out, ready to copy, paste, and send. Why would he send this to his sister I asked myself. I connected the dots and figured the message was for her. It said he wished he hung out with her more often, and that she was very attractive, and that he was lucky that she gave him her number without him asking, although he was going to ask if they ever hung out again. He admitted to having a crush on her. My chest felt crushed. How could he keep talking to her after he told me he had blocked her from all social media? Why did he tell her all of this when he had been desperately trying to get me back when we were on a break? Why would he tell me he loved me a few days before? Why would he hide this from me? How much longer was he going to hide this from me? Why me? Why are you here if you like somebody else? WHY ME? As he entered my room, I confronted him. Asked him why there were pictures of her in his gallery. Asked him why he sent her a paragraph of cute stuff when I had been asking for one for a million years. A cute simple random paragraph about how much he liked me and how he though I was attractive. He looked away and lied to me. He insisted that he was going to stop talking to her soon because she wasn’t into him and they rarely ever texted. I was desperate for answers. Where did he get the pictures from? “I made another snapchat account to keep talking to her” he said. My heart shattered. I felt angry. I felt sad. I felt humiliated. I felt confused. I still do. My chest feels tight with uneasiness. It finally happened to me. My boyfriend of three years cheated on me.