I think the meaning of the guy is this guy a singer, most likely a rock singer. He wrestled with some unknown problem, maybe the things that are usually associated with being a troubled rock star: drugs, alcohol, or infidelity. Nontheless, some demon had driven him and Sally apart. Probably Sally dumps him and seeks solace in Church meanwhile he, unable to help himself, keeps destroying himself. He's homeless, alone, and the world grows dim to him. Meanwhile her heart is so far from him. He is desperate. He seeks her out but she cannot be with this guy anymore and so he ends his life over a bridge where a river calls his name.