DP and I are moving in together in two weeks. He's suddenly decided that my kids need more "discipline" and "structure" so on the 4 nights a week he stays with us he's attempted to lay the law down about us having a "games night" 
where we play a board game and insisted that we all sit at the table to eat dinner. I'm really not happy about him trying to lay the law down like this and we had a small row about it and I said I would compromise by trying the meal at the table and would offer the kids the board game thing but not insist on it. So we're sat down at the table and it was really awkward and false. DP had "dressed for dinner" which I found absolutely hilarious and he tries starting shit conversations which all sounded so corny and sitcomish.
DS said something about "oh god, we're becomming one of those geeky families that think they're better than everyone else because they're smug" and DP snapped "well maybe it's about time you were aware of how you come across to others, there is nothing wrong with sitting at the table for a meal".
He was obviously implying that the kids had been dragged up and so I snapped and said he looked like a total dork in his "dinner wear" and he should stop thinking he was something wasn't. DS burst out laughing and DP snapped back "well if I'm a dork, you're a fishwife". DS again burst out laughing and I laughed along, it was quite funny. The dork and the fishwife. DP however sulked that it wasn't funny and he was just trying to be civilised "for once". For a laugh I agreed with him and asked DS to pass the caviare so DS flicked a load of mash at DP. It went all down his suit and I did tell him off and said he'd gone too far but DP was furious and stormed upstairs saying we were all beyond help.
AIBU to think that despite DS being naughty, the whole thing was caused by DP?