Reddit mentions of The Guest of Honor

I just came across this old 1989
book with a similar plotline

https://www.amazon.com/Guest-Honor-Irving-Wallace-ebook/dp/B00FWGJYQ8

If he had been just another married man, and she a beautiful woman...it would have been just a passionate affair. But he was the president.

MATT UNDERWOOD — President of the United States, a man about to risk his office...and his life — for love.


ALICE UNDERWOOD — The First Lady, a former Miss America whose lies could kill an affair or cause a world crisis.

NOY SANG — Ruler of a small nation, a woman so lovely that a president could do the unthinkable...and the forbidden...to have her.


HY HASKEN — Investigative reporter, he was after the story of his career — illicit love, powerful alliances, and murder.
RAMAGE — CIA director, his covert operations might be in America's interest...or they might be deadly games of power.

Once in a century a great — and dangerous — love can change the course of history. This was such a love.