For anyone seeking tunes about likely permanent estrangement, I concur with iTunes shuffle mode's judgment. This morning, it paired the Ultramarine remix of Everything But The Girl's "Missing" with "Slipping Away" by Dave Edmunds. Both songs offer roughly equivalent smidgens of hope, but I get the feeling in both cases that the couples will remain apart.
Such is life sometimes. Pulling off a melancholy tune with a compelling beat isn't the easiest task, but both artists strike just the right balance.