Background - H comes from a family where his dad married (and divorced) 3 times, having 2 children in each marriage (H being the oldest from the 2nd marriage, and his 2 older sisters continuing to live with his dad with after the 1st marriage broke down. His views about a step-parent actually being another mum or dad are very strong - to put it bluntly - they're not - and they never will be. They will be respected like a bio-logical parent would be, and will treat the child like a bio-logical parent would - but never call them mum/dad/son/daughter. He's had these views since we first met nearly 10yrs - and are views shared by the rest of his family.
So bearing this in mind - this afternoon - out of the blue - DS1 announced "we've got 2 mummy's" (cue shock from me and an "oh really" - yes xxx said it - exH's new woman). I waited until the DS's had gone to bed and called him - initially to check what was happening next weekend as he's still without car. Secondly to mention it........yes xxx had said something jokingly when DS2 had said "I've got 2 mummy's now" (which thinking about it I've heard him say before - even calling my best friend "the best mummy in the world") - but H made it very clear (nicely) to me that his views hadn't changed - and he hopes mine haven't even (if I have anyone new in my life they won't be "daddy").
He was clearly mortified by the whole thing - and I felt like such a twat - especially given DS2's apparent misunderstanding about who "mummy" is (even among my friends) and DS1's total lack of sense of humour