When they go to sleep at this point in their lives, facing away from each other doesn't necessarily mean a quarrel. Draping a hand over the other's hand, a leg over the other's leg, doesn't necessarily mean prelude to the old games of search and rescue. Like anyone else, they are tired from the exertions of a work day. Like anyone else, they know how a pulse quickens, how heat flushes through the courseways of the body. On weekends, they know how to turn off the alarm that rouses them from sleep so early on weekdays.