Stardust; Neil Gaiman

"Could it be that the heart that you seek is no longer my own? I have given my heart to another."
"The boy? The one in the inn?"
"Yes."
"You should have let me take it back then, for my sisters and me. We could have been young again, well into the next age of the world. Your boy will break it, or waste it, or lose it. They all do."
"Nevertheless," said the star, "he has my heart."