I think the girl might already know him, because he asks "would you want me when I'm not myself." So I always assumed that she knew him, he was simply asking if she loved him enough to go through the tough times with him, wait it out while hes "someone else" struggling with his inner battles. And once he has fought his fight and gained his footing again, he'll come around again for her, because even though he was acting different his love for her never changed, and she is his "saving grace," she motivated him and the thought of her got him through it. Anyway, that's what I got out of it the first time I listened.
I think the girl might already know him, because he asks "would you want me when I'm not myself." So I always assumed that she knew him, he was simply asking if she loved him enough to go through the tough times with him, wait it out while hes "someone else" struggling with his inner battles. And once he has fought his fight and gained his footing again, he'll come around again for her, because even though he was acting different his love for her never changed, and she is his "saving grace," she motivated him and the thought of her got him through it. Anyway, that's what I got out of it the first time I listened.