It just seems like the more I try to differentiate the more he just sees it as some kind of abandonment
Of course this happens. This is the part about "if you change, they will change." Except, they try to get you to change back to the way you were before so they DON'T have to change.
All this is about is that he has actually noticed.
So if he doesn't want to talk about it, if he wants to be bitchy about it... let him. Move on with your day. Let him sit in his office all night... yes... it affects your life.
So does rain. So does snow. So does the sun. But you make the best of those. To bemoan the weather, and ask why is it the way it is... is kind of useless... kwis?
And Fran, if he tries to pick a fight with you in a few days... you don't have to fight. (Even though it would probably feel really, really good.)