At first, they exclusively had sex together, but that eventually changed when Ana started living with them. To hear her tell it, her life with this couple was ripped out of the pages of a Penthouse letter to the editor. Rinse and repeat. While her living arrangement was somewhat unorthodox, she had been a unicorn a number of times before, starting when she was an undergrad in college. Threesomes are among the most common fantasies for couples, with an estimated 82 percent of men and 31 percent of women reporting having fantasized about a menage a trois in a Archives of Sexual Behavior study. And with