Kate Andersen Brower is a CNN contributor and the author of "First Women: The Grace and Power of America's Modern First Ladies" and "The Residence: Inside the Private World of the White House." Unless otherwise noted, facts in this piece reflect research from those works. The opinions expressed here are hers.

(CNN) Melania Trump's experience as first lady seems to be following an unfortunate tradition. First ladies have many things in common: no job description, no pay and, for many of them, humiliating betrayals by their husbands. The latest accusations against Donald Trump, as reported by journalist Ronan Farrow in The New Yorker, detail an alleged consensual affair he had with former Playboy Playmate Karen McDougal while he was married to Melania and before he was elected president. (Trump denies the affair.)

Although this kind of behavior appears to have been normalized throughout presidencies, it is becoming less and less tolerated by the public -- and with Melania Trump, by first ladies themselves. Following the latest allegation, Melania noticeably did not walk with her husband to Marine One before they departed to visit victims of the Florida shooting. This shift is happening, perhaps in part, because of the cultural shift brought on by the #MeToo movement.

Kate Brower

Before this shift, part of the bargain between many powerful men and their wives was that the women would look the other way when the men cheated, but they would benefit from the wealth and fame their marriages to such men provided. And for several first ladies, that meant sweeping infidelities under the rug.

Jackie Kennedy and Hillary Clinton are the most famous examples of this kind of compartmentalization, and, in many ways, they were the perfect matches for their husbands: intelligent, witty and, above all, discreet.

But they aren't the only examples. President Lyndon Johnson made no secret of his affairs and would often try to corner the prettiest girl in the room at a party. By the end of the evening, he'd have lipstick marks on his face. His wife, Lady Bird, would sometimes be in the same room and would plead with him to stop embarrassing her. "You're wanted over there, Lyndon. You're neglecting some of your friends," Lady Bird Johnson once said.

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