My husband made dinner that night, and seconds after my son and I finished eating, we collapsed. I forced myself to lie still as if unconscious, and that’s when I heard him whisper on the phone, “It’s done. They’ll both be gone soon.” Once he stepped out, I whispered to my son, “Don’t move yet…” What happened next was something I could never have predicted….

It had been weeks since Julian had cooked, but that evening, he moved through the kitchen with an unsettling kind of grace. Not a single movement seemed to be made without intent, as though he were trying to convince himself,…