Why would you cheat on your 54 year-old wife with a 49 year-old?
Actually, his wife is 48.
Lauren Sanchez is very good looking. Even more so for being 49.
At least Bezos chose a mature woman his own age. Much healthier than collecting harems of 20-somethings, which many do.
In the old days the king would have mistresses, and the queen tolerated them. As would most of the aristocracy and the haut-bourgeoisie for that matter. Wealth and rank had its privileges.