1 - You've been killed and turned into a revenant. Once reincarnated, you were forced to kill your love interest, however, you end up failing and retreated away, only to be pursued by those who wish to restore you to back to life.

2 (same as 1) - Your love interest was killed in front of you and turned into your revenant. Once they were reincarnated, they were forced to kill you, breaking your heart, however, they fail and retreat away, only to be pursued by you, the person who wishes to restore them back to life