So I'm probably being unreasonable but here it is.
me and my ex have a toddler daughter together. We're no longer together but get on really well and coparent our daughter.
hes recently started dating someone and it's getting serious. He's had other girlfriends before, but none were serious and none met our daughter.
the new gf also has a daughter but a few years older than mine if that's at all relevant.
also probably relevant, I do not like the new girlfriend. She's not an awful person but there's been a couple passive agressive comments here and there, and I get the impression she is really not happy about me and ex still being very friendly.
it's getting to the stage where he wants to introduce our daughter to the new girlfriend and I just don't want that. I have no real reason other than I don't like this woman and I don't want her in my daughters life but I also know that isn't really down to me. But my daughter is my world and I don't want this woman around her.