Themes
If, as I can’t help suspecting, the dead also feel the pains of separation (and this may be one of their purgatorial sufferings), then for both lovers, and for all pairs of lovers without exception, bereavement is a universal and integral part of our experience of love.
— C.S. Lewis • A Grief Observed

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Lewis speculates, tentatively, that the dead may also feel the ache of being parted. If so, loss isn't a rare interruption of love but part of it for every couple. He presents this as his own suspicion, not settled fact.
Context reviewed