Cautin: Dont fall for your bestfriend

I was told falling in love with your bestfriend is the best thing that could happen to any living being. I guess they missed the part where they should love you back in order to be perfect. I was the Victim of this saying. And i did fell in love with my bestfriend the closest to me in this whole world. I don't know how it happened but it did. Gradually his smile lit up my vision and guided the way. His caring gave my warm swirls i could feel whenever i though of him. It was slowly turning into me falling for him. I shouldn't have done this. I blame myself every second for doing this. He likes another, he knows i love him. He acts kind with me , how pathetic I've become for him to feel sorry for me. However i love him enough to let him be with anyone for the sake of his happiness. I know it kills me to let him go but seeing his smile is worth the whole world. I don't know what i should do. A grown up would face it as for me ill have a hell of fun running from confrontation.