Uxoricide

Having sold him the murder weapon makes you an accessory to uxoricide.

Terms related to familicide include filicide (the killing of one's child or children), uxoricide (the killing of one's wife), fratricide or sororicide (the killing of one's brother or sister), avunculicide (the killing of one's uncle), and nepoticide (the killing of one's nephew).

In order for someone to green-light a movie of this story, they’d need to have at least background knowledge of the sexual shenanigans of Sartre and Beauvoir, and of Althusser’s uxoricide – though not necessarily a close acquaintance with their published work.