amazingeugenie:

THE SUN AND ITS RAYS - LOUIS XIV AND HIS MISTRESSES. 
Many women of the upper echelons became mistresses for almost any reason other than financial benefit. Often they were married, socially well-placed and with a certain degree of independance. Once started, tact and iscretion were essential to the smooth running of the affair, especially in retaining a domestif status quo. And no one would deny that intrigue added glamour - and the thrill of danger - to the liaison.