Lene, what's here is too long to post as a comment to your post. I hope you don't mind. Anyway, here goes...You've had the chance to be with him late, so that's great since you've been missing him. He's your best friend and he happens to be a guy. Somehow, you find yourself feeling feelings for him. Afraid of ruining the friendship? Should you take a chance and go out on a limb?
Yes! Go for it. Don't run away from love. Get out of your comfort zone. The playing field is wide! Give love a chance. Learn to ask for what you want. If you're going down, at least you went down telling the truth, instead of denying it to yourself. Tell him, tell him, tell him.
No! Hell no! Zip it, keep it to yourself, leave things alone. Goodness, you're friends! Friendships last longer than romantic entanglements. Why mess up a good thing? Let him remain your dear p're. Be strong. Be brave. Do not cross the friendship line puh-lease!
Maybe? You've been friends with him for so long, right? Maybe you're shy to bring up the issue? How about dropping hints? Mention "I'm-in-love-with-my-best-friend" themed movies. Even better, watch it together. See how he reacts. Does he go all "ooooh! yeah, that's great"? Or does he go, "geez, that's all levels of stupid. I'd hate for that to happen in real life." If he reacts positively, tell him. If he doesn't want to ruin your friendship, just say it's just taking that friendship a step further. If he doesn't feel the same way (ouch!), at least you were honest to yourself and to him. Treat him like he's a person worth being honest to. I wrote this somewhere else before, "It’s a mark of a good friendship when two persons get past such situations. It can be awkward at first, but people do get over it."
Of course, you know him better than I do. Whatever you decide is totally up to you. Good luck!