I think I base my reading of this song mostly on the chorus, with the verses expanding on it a bit. There has been a relationship -- probably, though not necessarily, romantic -- where the two people involved growing as people also meant their growing apart. The character the song is sung to has grown from a "boy" to a "man", trading "fear" for "fire" -- but, in doing so, leaving. The relationship has helped him become himself, but that same development led to the relationship ending. And as much as she might search for an understanding of what changed, or what could have happened differently, his emergence into himself (with the "wonder" he finds at this) and his "leaving" are ultimately the same thing.
I think I base my reading of this song mostly on the chorus, with the verses expanding on it a bit. There has been a relationship -- probably, though not necessarily, romantic -- where the two people involved growing as people also meant their growing apart. The character the song is sung to has grown from a "boy" to a "man", trading "fear" for "fire" -- but, in doing so, leaving. The relationship has helped him become himself, but that same development led to the relationship ending. And as much as she might search for an understanding of what changed, or what could have happened differently, his emergence into himself (with the "wonder" he finds at this) and his "leaving" are ultimately the same thing.