A palliative-care doctor once told me that we die cell by cell until enough cells succumb that we cross over a line. But if you are watching the person you love the most die, you track their breaths, not cells. When someone is dying, their breath slows. Ever-widening gaps form between the end of the exhale and the beginning of the next inhale. In that space, you, the watcher, wait to find out if the unimaginable has happened. You don’t know if this breath is the last one, or if there is another to come. You only know it’s the last breath when it’s too late to go back and tell them you love them one final time.