Death By Toast?
She had gone through the house, gathered up everything that was his, and burned it.
She wanted no memory of him. She went to a hypnotist to literally erase any recollection of him that she still might have had.
But she had forgotten one very important thing.
He was making toast that godawful morning he passed into the next life.
She never liked toast, so she never had the need to use the toaster. She hardly even glanced at it.
That piece of bread was still wedged in there, covered with mold, hiding away from the world. The last piece of his life. The thing that proved their relationship had existed.
The only evidence was in the toaster.