promiscuitor
One who perpetuates acts of promiscuity outwardly; a slut, only in a more proper sense.
Guy: "Damn. I always thought Jenny was so sophistocated, but today she just walked right up to this guy and made out with him WITH HER BOYFRIEND WATCHING."
Other Guy: "Yeah, she always was quite the promiscuitor."
Other Guy: "Yeah, she always was quite the promiscuitor."