The mermaid princess in the fairy tale gave up her legs for the prince. When he was finally happy with someone else, she gave up killing the prince and sacrificed herself to become a bubble.
She is a real life mermaid. In order to love him, you can sacrifice your future and everything in your life, and even enter sex, just to be with him.
But when she finally has to choose, is it life or love?
She still made a philistine and realistic choice,
Kill him.