What happens when you fall in love with your best friend?

I’ve known him for a while. I’m sure he doesn’t feel the same way. We tell each other everything, play around a lot, act like we don’t care. I can’t help it though. I’ve tried to avoid it for a while now, but I can’t. I am way to big of a wimp to tell him how I feel. I know him, and I know if I told him how I felt he would act weirdly and our friendship would never be the same again. Anyway, that’s all.