Harry got together Hermione or Ginny, or whoever before the war ended.
A year after the defeat of Voldemort, and attack by Rookwood on the Burrow occurs. Harry sacrifices himself by tackling Rookwood when he tries to use a magical artifact.
He disappears in an explosion of light and magic.
He was separated from time, and reappears five years later. He'd aged, same as everyone else. But has no memory of the five years.
He is found unconscious at the same spot he'd vanished from.
But five years is a long time, families grow and shrink, and people move on.
Harry/Fleur