Well... almost one for every state.
[via: College Humor]
Answer: yes. One. And it's not humans (thanks, Maury!).
What's equally interesting is that there are several species of animals out there who, at first glance, appear monogamous, yet use intentional deception to cheat on their would-be monogamous partners.
Basically, if the animal kingdom had daytime television, there would be no shortage of guest applications.