He was my first love

He was my first love, [and] we dated for a year and a half. Around the year-and-a-half mark, he was going on a family camping trip with another family. A girl he used to have a crush on — who was dating a friend of mine — was also going. Even though they were just friends, I had this gnawing feeling he still liked her. When I asked if she was still going, he said no. The next day, I'm at a party and the boyfriend of this girl is at the party. I ask where she is and he was like, 'Oh, she went on the camping trip.' Immediately I knew that [my boyfriend] had cheated on me. He wasn't answering my texts, and when he finally came back, he came to my house said he was breaking up with me. Then when I asked why, he broke down crying [and] told me that he cheated on me and that he even had sex with her (this was supposed to be a family trip), which led to me screaming profanities at him and never talking to him again after that day.