Am I A Horrible Person?

Okay, so, I met this guy a few months ago. We immediately hit it off when we met. He's 18 and I'm 15, so my mom wasn't too happy about it. His aunt told my mom stupid, crazy, untrue shit about him. She said that all he wants is sex and he doesn't really care about me. She hasn't been in his life for the past 15 years or so and she knows literally nothing about him. My mom, of course, believed her because she doesn't like seeing things for herself. I snuck out of the house and met him. We had sex... And guess what! He still talked to me after that. He never asked for it. I went to him. My mom somehow found out. She had him blocked on EVERYTHING and we're not allowed to hang out anymore. We're not even allowed to look at each other. It had been a few months and I unblocked him. We've been talking and stuff, but he has a girlfriend now. His girlfriend, though, is horrible to him. She dumped him for her ex and when her ex didn't want her back, she ran back to him. Then, her ex came around again, she dumped him again and got back with her ex. She, then, got jealous of Chris' best friend, Loren (his name is Chris (her ex is Lucas)). She has nothing to worry about with Loren, they are just friends. So she dumped Lucas again for Chris. All in that time frame he was talking to me and fooling around with me. He keeps going back to her. How can I stop him from always going back to her?