The narrator compares himself to a bird that "cut its own wings" to stay with someone who offered very little ("alpiste" or birdseed) in return for absolute love.
It marks the moment of realizing that returning to a past love is no longer an option because the love that once fueled the relationship has died.
The track was born out of a friendship between the two artists. In 1977, while José José was preparing his album Lo Pasado, Pasado , he felt his tracklist was incomplete and asked Napoleón if he had any "spare" songs. Napoleón responded that he didn't have songs to spare, but he did have one he specifically wanted José José to sing. At the time, the song had no title; José José chose the name "Lo Que No Fue No Será" from a line in the lyrics. Lyrical Meaning and Metaphors