I took on the AU time line of married with children later in their careers, say mid 30's. So given they're required to leave the field at age 40, the family scenario works. It's not all happiness for them though, and there are some tumultuous times, and an angst-ridden situation thanks to a former UNCLE agent turned THRUSH.

So I don't make my AU family stories full of all hearts and roses, to say the least. Most importantly Illya and Napoleon remain dangerous agents in the world of espionage...but they're still human, with human frailties and desires.