Right now you have this person on a pedestal, to make matters worse they're unavailable which makes them even more desirable. In most cases the reality doesn't equal the fantasy. Whilst thinking about him you'll be thinking about all of the great things about this person.

For a moment, can you suspend this belief, nobody is perfect, what's not perfect about him. You won't get rid of these feelings overnight but if over the next few weeks /months you think of a new way in which he's not perfect everytime you see him you have a good chance of diminishing these feelings to the point where you are no longer in love with him.

When he does something that bugs you, remember it, come back to it your mind. This is pretty much the same way many people fall out of love. They start noticing more of the bad qualities than the good.