Help!!

I fucked up real bad & I need advice. There's this boy that I've been seeing for about 8 months kinda on & off but more on than off yano? But it was never something serious. More like a friends w/ benefits type thing. I'm pretty sure he was seeing other people, as was I. He made me really mad earlier this month so I stopped talking to him for a while, like about 3 weeks. During those weeks I started flirting and liking another boy in my class who happened to be boy1's nephew. It didn't feel right when I thought about it but I didn't see any wrong in it. So boy2 called me and wanted to come over that weekend and I let him bc I didn't have anything else to do Yano. We end up having sex by the end of the night. But then I go through his phone & he's telling me the same thing he's telling other girls & I get pissed. Boy 1 called me the next night & I let him come over. He's the only one who can hit it right so we ended up having sex. The next week they talk and find out so they're both mad at me & now I know how fucked up & dirty that was & so I'm looking for a way to fix it. Can someone help me. I don't want to lose boy1.