Contact with half-siblings when joint parent is useless

[RishiRich]

I'm just wondering what other people do or would do in this situation.

ExH and I have 2 DC together. After we divorced he got remarried and had another child. He and his new wife split up and he has no contact with either of them and sporadic contact with our DC. The DC were all quite close when they used to see eachother EOW.

Our DC are pre-teens. The other child is a lot younger but still remembers my two and knows who they are.

ExH is adamant that I am not to contact his latest ExW. She and her DD live a short flight away from us. ExH lives on the other side of the country.

I went against ExH's wishes and arranged for the children to visit. He was furious but they had a lovely time and asked to go again.

WWYD?

I don't know what other people do. But I think you are doing the right thing. Your children have every right to have a relationship with their siblings, and his disapproval or anger is not a reason to stop you reaching out to his latest ex and maintaining that relationship.
Why is he so angry about it? Why has he cut contact with his other child?

My kids have a half sibling on exes side, I’ve never contacted them and they have never contacted us.

It's not up to him, the DC want to maintain a relationship.

Who made him king of who you have contact with? Unless you are afraid of him or rely on him financially, I would crack on.

If the kids want to see each other and you and their mum are happy then crack on.

He's angry because he thinks his ExW and I will be talking about him. We didn't last time and I can't imagine either of us are particularly interested in talking about him TBH.

I don't know why he doesn't have contact with his other DD. Apparently he used to phone her quite regularly but it petered out.

He pays no child maintenance to either of us and we're in no way reliant on him. However, he can be quite scary and I had an NMO awarded against him at one point. He's unstable and erratic.

It really isn't any of his business.

It would be better if he arranged for the DC to see eachother. He promised he would but hasn't, so I have.