The mutual loathing society.

As we know, John doesn't really respect Elly all that much; he likes to play mental games with her, he doesn't seem to want to admit that his cruel, thoughtless remarks are not only setting a horrible example for his children, they're giving Elly a legitimate grievance and he makes light of any ambition that takes away from servicing his needs. The only bright spot is that Elly doesn't really respect him either. We know for a fact that she doesn't think much of him as a husband or father, she doesn't like his friends or the job that keeps her from having to sell her blood in order to survive and hates the things that interest him. The only reason I can think of that they haven't killed one another is that they hate other people far more than they loathe one another.