A faithful spouse is what is missing.
I have to agree with beandog. It’s true that in some cases a man strays in part because his wife neglected him in some way, but that is more of a convenient excuse than a real motivation. First, it’s every spouse’s duty to avoid emotional entanglement with members of the opposite sex that may send them down the wrong road. Second, I’ve known a wife or three (and a couple of husbands) who were doing everything they could to make their marriages good and got cheated on anyway. Some people just allow themselves to care more about their groin than their spouse and kids. Some guys turn their mid-life crisis into an “excuse” for their fickle pickle.
That’s not to say that’s the situation in the Sanford household (for all we know Mrs. Sanford is Eve Ensler with a Southern accent), I’m just saying that in almost all situations cheating is about the cheater, not the cheater’s spouse.