My ex's new partner has kids. Despite him not wanting more.

[Justkeepswiimming]

I'm trying not to let this sting, but I can't help it. He shut down the possibility of us having a second dc, despite me wanting more at that point. Now he is in a relationship with a woman who has two kids. I'm not sure what I'm struggling with the most. This or the fact my daughter has ready made siblings. Something I'm not going to be ble to complete with. Please me gentle. I know I'm being that woman but I'm finding this quite painful. Any advice or experiences would be really appreciated.

They aren't his kids. And blended families are hard bloody work!! Allow yourself to feel hurt by this but know the pain will lessen with time. Imagine he's miserable feeling lumbered with two more kids in his life.

You are grieving the breakdown of your relationship. But it will get better.
As to the "ready made siblings" - this isn't what blended families turn into. They aren't siblings and you are not competing with that, or with anything really.

If you want another child, btw - have another child.

They are not your daughter’s siblings and never will be.
He hasn’t had more children, they aren’t his.
It will be a miracle if it lasts.

It's not quite the same when they are someone else's kids. He's not ultimately responsible for them and he hasn't had to deal with the baby years - which some men cope poorly with.
A drop in intimacy or sex life will not be a factor either, so you can't compare. He might actually like that she is less likely to want more too. Now, if they go on to have one between them, that could raise an eyebrow maybe, but this is not significant.

He won’t have even noticed her kids. They will just be part of the package.

Sorry to say, but since time immemorial, people who didn't want kids, or more kids, suddenly wanted them with the next person. I think more likely with men, but have seen this with women too. Sorry that he was a shit.