| Runnen brings up a good point. A History of Violence is a good example. It's got some REALLY sexy scenes in it along with frontal nudity...
... but it didn't get labeled as a film about sex.
In fact, American audiences are really sort of bored with films about sex. Eyes Wide Shut didn't do so hot at the box office and neither did Basic Instinct II or other films about sex specifically. It's when sex is mixed in with some other story that it becomes worth watching.
HoV is a good example where the sex added to the story. It established how much in love the two characters are, what the chick is willing to do for her man and how they have a healthy sexual relationship. Goodness forbid Hollywood actually show two people having sex that actually LOOKS LIKE two people having sex. | 