It's a song about struggle. A couple who wants to improve, either become the best they can be, or escape from the bad place they are in. But as they both strive for this, as a couple, they both fall short of their goal, they just can't get there. Either they have something that keeps holding them back (illness, drugs, society, etc.) or they have they their sights unreasonably high and continue to fall short of their expectations.
It's a song about struggle. A couple who wants to improve, either become the best they can be, or escape from the bad place they are in. But as they both strive for this, as a couple, they both fall short of their goal, they just can't get there. Either they have something that keeps holding them back (illness, drugs, society, etc.) or they have they their sights unreasonably high and continue to fall short of their expectations.