what can i do about it?

I'm afraid there's nothing you can do about it. Don't try to break them up and destroy their relationship because the guy you like will then never like you. You just have to except the fact that they're together and get on with your life.

Continue to like this guy. There is nothing wrong with it. If he breaks up you can be there to console him. Make sure though that you don't hang on desperately for long periods of time. There are other fish in the sea. Make sure that you give someone else a chance if necessary.

well girl listin here i have had so many crushs befoe and i always had dated them idk how i tha happens but really i l;earn tha crushs should stay crushs dnt go forward and try to break up the couple if the girl is mean az lyk u say a person could only take a bad gf foe so long so if he lyks u lets say well he'll ask u out but foe rite now just let it be yo crush faith haz its ways rememeber tha!!!!:)hope tha kinda help!!!