Actually, dissociation of character is a trait that is rewarded.
Although people will claim they want kind-hearted people as lovers, they also very often conveniently ignore what they do for work, and how cruel they have to be, and the partners happily enjoy the shared money (or respect they have from the world). Lovers surely know it: hard to claim Che Guevarra’s wife, Stalin’s wife or Pablo Escobar’s wife didn’t know anything about drug dealings, but it shows that what people actually fall for are people who are nice... with them, and ruthless to the outside of the family.
So the John/Jake dissociation is unfortunately a road to success. I say unfortunately because it brings swathes of problems: John doesn’t mind having less ethics than Jake; wives who suddenly are dumped find themselves on the outer side of the fence, at risk, and very close to a very brutal human; and the last unfortunate corollary is that violent humans who can dissociate (and be someone else in private) reproduce easily from generation to generation. Hitler, Stalin, Che, Saddam Hussein have wives and Salah Abdeslam (the French terrorist, as famously any other mass killer) receives love letters, while people who won’t reproduce include Beaudelaire, Newton, Tesla, the Wright brothers or Alan Turing.
The Jake/John dissociative trait is very interesting.