When you're single, you pick sex over sleep. But once you've been having sex with the same person for a little while, sleep beats sex. And apparently, the pendulum eventually swings even further . . . and you pick sleep over two seconds of affection.

According to a new survey, 80% of couples say they go to sleep without even a quick goodnight kiss. Not even a peck. They're just in such a rush to go to sleep they don't bother.

90% of couples don't say "I love you" before they go to sleep.

The survey also found that 46% of couples sleep with their BACKS to each other . . . and only 1% sleep like couples sleep in the movies, with the woman's head on the man's chest.