The lyrics are written from the perspective of someone facing their own mortality (dying from cancer) and attempting to come to terms with the fact that their "forever" is ending much earlier than expected.
Herbert wrote the song after the death of his uncle, who he considered a second father, from cancer. Forever Came Too Soon
While Herbert's album is the most prominent "paper" or work with this exact title, other artists have used similar themes: The lyrics are written from the perspective of
Features lyrics about a "paper heart" being torn apart and the line "You said we'd be forever, but forever came too soon". who he considered a second father