Now you may know why you usually have a disturbed sleep at night - go figure out if your wife has higher marital satisfaction!Couples are more likely to sleep in sync when the wife is more satisfied with their marriage, a fascinating research reveals."Most of what is known about sleep comes from studying it at the individual level. However, for most adults, sleep is a shared behaviour between bed partners," said Heather Gunn, a post-doctoral scholar at University of Pittsburgh.Read: Couples sleeping less than an inch apart are happiest!"How couples sleep together may influence and be influenced by their relationship functioning," Gunn added.Results show that overall synchrony in sleep-wake schedules among couples was high, as those who slept in the same bed were awake or asleep at the same time about 75 percent of the time.When the wife reported higher marital satisfaction, the percent of time the couple was awake or asleep at the same time was greater.To reach this conclusion, researchers studied 46 couples who completed relationship assessments.Objective sleep data also were gathered over a 10-day period."The sleep of married couples is more in sync on a minute-by-minute basis than the sleep of random individuals," Gunn noted."This suggests that our sleep patterns are regulated not only by when we sleep, but also by with whom we sleep," she said.The research was published online in the journal Sleep.