To me it seems like he is down because of the other person, he/she left him or dind give him a chance, didnt care about him. But still he would do anything, even sacrifise his own life to save the other person, when he/she starts to fall apart.And he expects the other person (after using his help) to leave him alone in the dark. Its strong contrast - even in the intonation of the singer - i would do anything i can for you, but i now that youll always leave me down a you will never take care about me and i dont expect anything else of you.
To me it seems like he is down because of the other person, he/she left him or dind give him a chance, didnt care about him. But still he would do anything, even sacrifise his own life to save the other person, when he/she starts to fall apart.And he expects the other person (after using his help) to leave him alone in the dark. Its strong contrast - even in the intonation of the singer - i would do anything i can for you, but i now that youll always leave me down a you will never take care about me and i dont expect anything else of you.