She's calling herself mum front of my kids, as in that she is their mum! AIBU being upset by this? DH said it's a slip of the tongue and she doesn't mean any harm but she's said it at least 7 times and it makes my blood boil. The kids are young so haven't really noticed I don't think, I hope not anyway. I asked her what the hell is she saying that for and she said oh silly me sort of thing but I think it's a bit below the belt.