"Best Friends" problem?

There's this kid (I'll call him Chris) who I have been good friends with (minus this last year) since 6th grade. We kind of became "best friends" by default when my childhood best friend moved half way across the country. It hurt when me and my childhood best friend grew apart, but that's just he way it is. I will admit, me and this kid did have fun, but I definitely had other really good friends too. We'd hang out probably 2-3 times a month (a decent amount of time considering we couldn't drive). The thing is, we didn't have much in common at all, but we both wanted a good friend, which made it easier to get along. But, when other people that I had a lot in common with would come along, naturally I would hang out with them a lot too. Usually, they wouldn't get along great (not bad, just not people that would usually hang out) with Chris. Chris would get pretty jealous, but I always kept his friendship because I knew he was a nice person and didn't want to hurt his feelings. This went on for about 3 years.

Then, in my Junior year me and this kid Dave would hang out all the time, we would do hilarious things and had a really good time together. I still tried to keep Chris a good friend of mine to be a good friend, but I honestly started having waaay more fun hanging out with Dave, and over the next 2 years me and Dave were such good friends people thot we were gay haha. Chris still fully assumed we were best friends, but would get extremely jealous and always ask basically why he felt I liked Dave better. I had to tell him Dave was my best friend, too. Me and Chris roomed in college freshman year and it completely ruined whatever was left of our relationship. I try not to sound like a jerk, but Chris just annoyed the crap out of me. I always felt guilty cuz he would make me feel so bad for not being "as loyal as a friend as him" and I felt really bad (and still do). I still considered him a friend, but not a best friend. People grow apart sometimes, I can't help that. I tried to keep things at bay, but it's got super bad this summer.

I make myself available to hang out around once a week, sometimes 2. He left a really angry voice message last night like, "WHY THE f*** IS IT SO HARD TO CALL ME I'M YOUR BEST FRIEND" and saying how he's so much more good of a person then me basically. He called me crying last night demanding to know why I can "never hang out" and don't make him the priority over my other friends. Hanging out is never EVER fun at all anymore because he's so bitter about me. I feel like such an aweful person the way he talks to me but he really treats our friendship like we're married or something. He tells everyone we're best friends, has asked me to be the godfather of his child, his best man, if we can get an apartment together after college, saying he'd love to, why don't you want to!? After saying that stuff he expects me to say "can you be my child's godfather", "will you be my best man"?, ect. It's driving me crazy. I told a mutual friend of ours the situation (he just came back from VA), and like me, he feels bad for Chris, but at the same time thinks he's way to needy and inappropriate the things he asks/expects of me. He thinks I should straight up say we're not best friends (cuz he does not pick up cues, I literally hang out with Dave 2-3 times a week, and other people more, too) I'd include Chris but he just ends up getting mad at me in the end. It turns in to him obsessing over why I'm hanging out with someone, and why I can't hang out with him (Chris) instead.

If anyone has any advice on this hard issue, please tell me, I'll be really grateful. Please don't call me an a$$hole I've just got to the point I don't want anything to do with this kid he makes me so unhappy.