Religious boyfriend

Me and my boyfriend met a year and a half ago. It was casual sex at first and then we both caught feelings. Oops. Things are now pretty serious. But, he is very religious and I'm an atheist. After I realizes I had very strong feelings for him, one day we talked about religion and homosexuality and he doesn't think gay marriage is a thing. He also believes that people can give them souls to Satan in exchange for material things. I am a science major and beyond dumfounded at his bullshit sometimes. I try not to let it get to me because he's a good person overall but I think I can do better?? Like why should I be with someone that I think is not as intelligent as I am? Am I wrong?