I would imagine this song is about a relationship he feels need to end. She's created some disillusioned idea of their relationship, probably thinking about the future too soon, "a picture that I just don't see"; the relationship was going well, so why is she expecting even more ("Why do you have to make it so complicated / Can't it just be beautiful"? He was in love, but now, it's just not the same. He can't remain with her knowing that she's expecting something he can't give her. He'd rather end it now so as to preserve the goodness of what they had.
I would imagine this song is about a relationship he feels need to end. She's created some disillusioned idea of their relationship, probably thinking about the future too soon, "a picture that I just don't see"; the relationship was going well, so why is she expecting even more ("Why do you have to make it so complicated / Can't it just be beautiful"? He was in love, but now, it's just not the same. He can't remain with her knowing that she's expecting something he can't give her. He'd rather end it now so as to preserve the goodness of what they had.
Describes my last relationship to a T...