"Disparity"

 There are those who say she's loose or promiscuous
A larger group will label her as insatiable, a nympho or sex addict
Smaller groups whisper slut, harlot, trollop, whore
Fewer still have her back, do friends defend every attack

Many refer to him as a womanizer or ladies' man
Many more say he is a Casanova, Don Juan or Romeo
A minority might use lecher, libertine or whoremonger
Friends will joke, he's a stud or gigolo

Disparity