Edith Wharton, who was born on this day in 1862, pointed it out in her book The Writing of Fiction:
As to experience, intellectual and moral, the creative imagination can make a little go a long way, provided it remains long enough in the mind and is sufficiently brooded upon. One good heart-break will furnish the poet with many songs and the novelist with a considerable number of novels. But they must have hearts that can break.
(h/t: Roxane Gay)