My wife sleeps later than I do. I hadn’t thought about this too much. We tend to go to bed at the same time, and she sometimes stays up later watching shows on her computer, but she sleeps quite a bit later. However, I finally started putting it together.
Just consider these as a relative sample:
Yup, my wife sleeps later than I do because she’s up all night taking pictures of the cats sleeping on me. I suppose everyone has to have a hobby.