Again and Again

A millennia has passed since the creation of the Original family though one detail of their history is often left untold. Near the end of their human lives, the vampire Klaus met a young witch. After he turned, their relationship continued and when he was cursed, she was as well.
Mikael, determined to prevent his wife's bastard child from experiencing lasting happiness, had his werewolf side locked away, and his love cursed to be reborn every 50 years only to die before she reached 30.
When the originals show up in Mystic Falls, there's more than one reason they wish to end the curse.