Sting sings (a part of) Noel Cowards \"I'll follow my secret heart\". This rather unknown cover by Sting is from the album \"Twentieth-Century Blues, the songs of Noel Coward\" (1998).
It's a delicate song in word and music. In short, I think it's about the \"other life\" people want to live, opposed to the life they lead. In their eyes you see a wish to follow their secret heart, but the time isn't right yet. Or you see a quenched look because they failed to use the opportunity to follow their secret heart.
On the bright side: life isn't doable. To paraphrase mister Lennon: life is what happens to you while you're following your secret heart, busy listening music.