This one isn't hard for me because I lived it and still am. He has to love her from afar, because she doesn't love him. They are friends, but he wants more, she doesn't though hence "That's not the way friends behave." The "crumbs of your love" is the taste of her love, that he gets through their friendship. The line "you light me up, from across the room, two fallen sparks, one willing fool" could mean that they both have been hurt by love before and he is a "fool" and willing to take the risk of loving her, but she rejected him because she has been hurt to many times and now he is forced to love her from afar "and that will be the way [they] remain". But there is some bias in my interpretation, so i could be wrong.
This one isn't hard for me because I lived it and still am. He has to love her from afar, because she doesn't love him. They are friends, but he wants more, she doesn't though hence "That's not the way friends behave." The "crumbs of your love" is the taste of her love, that he gets through their friendship. The line "you light me up, from across the room, two fallen sparks, one willing fool" could mean that they both have been hurt by love before and he is a "fool" and willing to take the risk of loving her, but she rejected him because she has been hurt to many times and now he is forced to love her from afar "and that will be the way [they] remain". But there is some bias in my interpretation, so i could be wrong.