Friendship evolution

Ever have one of those friends who's been your friend for so long, you just can't imagine not being their friend anymore? This even when you realize you that you really just don't enjoy that friend's company anymore?

My best friend from school and I still keep in touch. He lives across the country from me and we see each other on IM all the time. Every so often we'll have random chats on line. Lately, I've realized that I can't enjoy these conversations anymore. I'm tired of watching what I say for fear of being belittled or condescended to. I'm sick of avoiding certain topics of conversation knowing that I would just get dragged into some stupid-ass argument over nothing.

When you realize that you simply don't enjoy talking about your everyday life with your best friend anymore, what are you supposed to do?

He's coming to visit next weekend with his boyfriend. Thankfully, they're staying in a hotel. I'm taking a day off to hang out with them. I'm not dreading hanging out with them, but I'm not necessarily looking forward to it the way one would expect from a visit from a good friend. If we get into another fight about some stupid, trivial matter, I may just blow a gasket.