I'm starting to be really attracted to this guy, but I have a boyfriend, how can I stop being attracted to him?

I love my boyfriend and would never want to hurt him and I don't want to stop being with him, but it's gotten to the point where he wears basically his pajamas when he comes to see me and doesn't bother shaving or wearing glasses and he's stopped going to the gym. I'm not shallow or anything, but we're both so comfortable with each other that we just don't even try to impress the other anymore. I've always wanted a really stable, serious boyfriend and I've never been interested in just dating for fun and I've never had a problem with our relationship. BUT now I've become friends with this super great guy and he's the cliche hot guy and he's also super nice. He's not a player and he's kind of shy but he has a super hot body and a really cute face and he sings and plays guitar. Really well. He's becoming the friend who helps me with my problems and is really good at cheering me up, but my boyfriend makes me soooo happy and I love him and I'm worried because I'm more attracted to the other guy. How can I make my feelings for my friend go away? I could never break up with my boyfriend over something so selfish. He's such a great guy.