help, please

is there some list of rules of communication that you are supposed to follow when dealing with someone you slept with previously? i ask because, at lunch today, i was giving mr. m a good natured ribbing (as is my habit - it's sort of the basis of all of our lunchtime conversations. has been since we started having lunch together almost a year ago. and i'm not the only one - he's really easy to embarrass so most of our lunch group kind of delights in doing so.). see, i've noticed that, since christmas, he's been making changes with his appearance: growing a (rather sparse) goatee, undoing an extra button on his shirts, wearing a thick gold chain. today he was also sporting a gold bracelet. i asked "what's with the bling?" and wondered aloud whether or not he's having a mid-life crisis. now, i know the answer to that question, since i WAS his fucking mid life crisis (pun intended). but i said it rather good-naturedly, and the table laughed. he, however, got quite rude with me and it was pretty uncomfortable. so i pretty much rushed through my lunch and left the table.

now i'm wondering if, because he fucked me for 7 months or so, i'm no longer allowed to behave towards him the way i always have behaved to him, and everyone else for that matter. i'm wondering if he's operating under some set of unwritten rules that he's not seen fit to make me privy to. if so, i'd rather avoid that particular minefield entirely and just eat my lunch alone at my desk, thanks very much.

(see, if i was his wife i'd figure he's having another affair. so if i start getting irate phone calls again, i'll know what's up. unfortunately, i'll be clueless - not that she'll believe me. oh i hope she calls - i can say all of the really lovely things i held back when i was worried about upsetting mr. m)