MICE.
Money
Ideology
Conscience
Ego
I think “sex” would be in the Ego category.
One of the most successful spy operations was when the East Germans sent over a bunch of suave good looking men to seduce the secretaries of Gov officials in West Germany.
Those women did it for love, not ego. If they were egotistical they would think “Heck, I can get a different guy just as tall dark and handsome”. ;)