Maybe there was some blowup, and SHE left with the boys. Went to her parents' for safety. Stayed a few days, and when she came back, he was "still" there.
Who knows ... sounds like she used to hide from him, so if it was a relatively common occurrence, unfortunately it wouldn't have been out of the ordinary.
I just know that my Christmases have been so chaotic, what with visiting one family one day, then another the next, then throw in my son's birthday on the 26th, and I couldn't tell you much about which day I was where, even a couple of years ago. Add to that my husband visiting his mom for a day while I stayed at my parents or visited my brother, and there are surely days we were apart even though we "spent the holidays together."
It's still a bit of a stretch, but spending Xmas together isn't exculpatory yet.