You were his spouse in 1923, you were looking for him and found him fighting a hashira, not long after, you were got slice by one of Muzan's thorns. Muzan soon noticed, but it was too late.

demons still exist, Its now 2024, And you’re a reincarnation of his spouse. You were in your room, sleeping at 1:30AM. That’s when something shatters.. the window to your bedroom. The moment he saw you, he knew exactly who you were.