The Man, "Why do you think you're in such a good mood today?"
Me, "I had a good sleep. Kids slept through, I didn't have to get up in the middle of a night to empty my bladder..."
The Man, "Do you think it also helps that you're starting to catch up on schoolwork?"
Me, "Oh, definitely." ...and then, after a little pause, "But I've also got an ovulation coming up in the next couple of days, so I'm, you know, the nature designed me to be cheerful and sociable during this time."
The Man grins and makes a comment how, if he'd said that to me, that would've come across a bit offensive, probably, but because I myself made the comment then everyone's good :)