This is a textbook example of pathological narcissism and the rage that results from the gap between desired self-image and reality.

This is why the guy whose girlfriend is trying to leave him decides to kills her. It's because he needs to be seen as someone who "has" a woman. The idea that she doesn't want him is perceived by him as a deadly threat to his self-image, so he kills her in retaliation.

That's the thing you have to get about pathological narcissists; they perceive threats to their self-image as someone literally trying to kill them, and they respond accordingly. To them, it seems like self-defense. This is why you get mobs of angry trans activists trying to attack people who refuse to validate them.