I was curious exactly what was going on at night when we slept, so I set up a camera for a couple nights to see. I found out that my wife's waking up was mostly my fault. I'd toss or itch my nose in my sleep and smack her, then turn over, she'd wake up wondering what just happened
For me, temperature and position are important. If there's any speck of dirt or crumbs from something in the sheets, I can't get comfortable. Also the cat randomly hops into bed and will sleep on us or between our feet and when your body stops being able to move the way it wants to, it wakes up.
Overall, it seems the days that I really tire myself out (like several hours wrenching on the fiero before bed), I sleep the whole night.
