After Christmas I received an email from a former coworker, Nadine, who had recently become widowed.

She asked whether I would meet her for lunch.

We had spoken in passing at work for years, but neither of us had found time to develop a friendship outside it.

We met at a diner near the library, where she confessed she no longer knew how to order food without thinking of her husband first.

“I keep choosing what he’d have wanted,” she said.

“Then I remember he’s not sitting across from me.”