mother was a narcissis and sociopath

My mother was also a sociopath and narcissist and some evil. I could write a book about her manipulative, devious, cruel, self-centered, phony, lying, etc personality.

But, the one thing about my totally screwed up family that I will never understand was my father. Will someone please explain to me how a man can stay with a woman who treats him like dirt everyday of his life and also allow her to abuse his children and make everyone's life miserable except hers. Why would he stay. My father was spineless and a wimp who I had no respect. I am sorry to say that but it is true. Why would he allow this to happen to himself and his kids? Please anyone have any thoughts. Thankyou