My Boyfriend and My Best Friend Hate Each Other

I don't know what to do. I have a boyfriend, I've been dating him for years and I love him very much. My best friend, not so much. He hates him. I know it isn't jealousy, my best friend does not swing that way. They both know I'm not going to choose between them because I love them both and can't let them go, so they just don't speak to each other and try not to fight for my sake. I feel so bad about it, I really want them to get along. My best friend hates my boyfriend because he thinks he treats me badly (he actually just hates anyone who hurts me ever, no matter the circumstance) and my boyfriend hates him for judging him so harshly. My best friend is flying up to visit next month, and it's really hard to see one of them without the other, and there is no way I can allow them to be in the same room together. Seriously, it's like having Thanksgiving and inviting your dad and his ex-wife. I know I can't make them like each other, I just don't know how to cope.