...for successful conservative male politicians.
As conservative politicians, they are bound (morally speaking) to uphold heterosexual monogamy as the foundation of civil society.
Which, of course, it is.
But, as successful males, they are also bound (a-morally speaking) to cheat on their wives - men being what they are, and the opportunities for successful males being what they are.
Add in the all-seeing gaze of the modern media, and the only conservative male politician who can possibly succeed in the long run in the U.S.A. today must be either a saint or a eunuch.
Rare folks, these days, saints & eunuchs...