My Sword is Divine After I Crippled the Protagonist

I was reincarnated as the cannon fodder side character in a cultivation novel.
The poisoned heroine lay dying in the protagonist's arms. 'Michael, don't beg her. Even if I die, I want to be with you,' she whispered.
At her words, the hatred in the protagonist's eyes towards me deepened.
So without hesitation, I disabled him with a single sword strike.
Under my parents' astonished gaze, I smiled demurely and said, 'With no man in my heart, my sword becomes divine. The first page of the sword manual: slay your beloved.'