I fell in love with my ex friend’s ex.

I’m 15 years old and a sophomore in high school. A little of back ground information. My friend, lets call her E, was my best friend freshman year. Our friendship ended because she would say that I was a whore behind my back. I met a guy, let’s call him C. C was my boyfriend for about 3-4 months. E texted C and C cheated on me with her. I was devastated. I’m still talking things out with C, but I don’t think I’ll go back. I know somewhat my worth lol. E has an ex and lets call him A. A is the funniest guy I have met. He’s absolutely amazing but he has a history of being a cheater. Him and I became friends a couple of months ago. We started a friends with benefits situationship about 1-2 weeks ago… and it’s going bad. I like him and I don’t know if he likes me back. He is absolutely amazing and treats me well. E isn’t happy over this and she keeps making rumors about me at school. I want to tell C about A but C and A don’t get along. I don’t know what to do, A and me link up at different places so people won’t see us. If I could, I would choose to be with him. He treats me good and I love spending time with him. What do I do?