I love reading about the many ways the ghosts of our past can haunt us: in memory, in songs, in the person we glimpse in the rear-view mirror.
One wonders if Harold ever thinks of her when he watches his kids. It’s they, in a sense, who are the reason that he and Barbara aren’t together. And, while such an ideas is a bit of stretch, our protagonist does the radio off when driving alone because of her. She’s apparently only ever one reminder away.