Our regular single guy is 28, we are both 47, the "could be your kid" jokes need to stop

minor rant incoming bc i need to get this off my chest. me 47, dh 47, MFM dynamic with a single guy we've been playing with for almost a year. he's 28, very chill, very respectful, came to us through a friend, plays only with us, has been a great fit. theres a 19 yr gap between him and us which on paper sounds dramatic but in practice basically never comes up except for one thing — the jokes from OUR FRIENDS. like, in the lifestyle, with couples our own age who know about our arrangement. every single time it comes up at drinks or at a club, somebody — and its always a different somebody, like its rotating — drops the "ha could be your son" line. or "oh you're raising him well". or last week one of dh's mates said "youre basically his second mum at this point" and i laughed in the moment and then was annoyed about it for two days. these are friends. theyre not being cruel. theyre being lifestyle-jokey in a "we're all comfortable enough to rib each other" way. and yet the jokes specifically about parent/child dynamics are starting to grate. they make him sound less than the adult he very much is, and they also make our connection sound like its something other than what it is. oh and honestly it just feels lazy too — there are infinite jokes about MFM dynamics that arent about pretending hes a child. dh thinks im being oversensitive. our guy laughs them off but ive started noticing his jaw set a little when they happen. id like to push back on it but i dont wanna be the no fun friend at the table. anyone been here. is there a graceful way to retire a recurring "joke" without making it weird at the next event.