To have nothing further to do with them?

That doesn't mean it wasn't said.

Yes she was.

It got deleted though...

Then you should have read the full thread.

They always spent Christmas with you, and not BIL’s parents, and yet your MIL got arsey when they decided to spend Christmas with the grandparents they didn’t usually see? Doesn’t she realise she got every Christmas for years? I would find that reaction really annoying

I'm thinking that perhaps the problem between your DH (and you) and his sibling needs to be addressed first. Have you even tried to discuss this with them? It seems a bit weird to "go nuclear" without even a discussion.

Look at the bigger picture the problem is you.

Your DC wouldn't have known the other kids at the party. Children usually ask school friends to parties. And they did come over next day with a cake. But you took this as an insult and stormed upstairs. It seems to me a very good way of celebrating their DC birthday. Party with mates and a fun time with cousin.
Yes it is good to have cousins who are close to you,but honestly you sound a bit pushy.

oh here we go 🙄 neurodivergent.....
Maybe it's your entitlement that's a problem.

You are projecting your own issues onto your child. That is not good parenting.

you have over reacted about this. My children don't invite cousins, just their school mates. When they DO see their cousins they have a great time and it's special in a different way.

YABU. At age 7 kids are making their own friends at school. Inviting a cousin from another town is awkward because the other kids don't know them, and it can put the birthday kid in a stressful position.

A separate celebration with the cousin is entirely appropriate.

Op I think this is a huge overreaction. My daughter is 7 and has a cousin who is 7 who came to her first few parties. But, by year 3 of school, the birthday parties are smaller groups of school friends and usually doing activities so numbers are limited so my daughter prioritises her school friends to invite to the party. I think that's very normal. Then we will have a separate little tea party for her grandparents and Cousin etc. which is exactly what your Sil has done!!
But no one here is offended!!!

No you are not being unreasonable if that’s how you feel but maybe ask them why the distance instead of cutting them off. I can see why you are upset though because if my DC felt left out it would upset me too.

Have you actuallh ASKED what the problem is and expressed how hurt you and your DC are over not being invited to the party?

Can I ask if you have a social worker? If you do, could she arrange for you to have a counselling or coaching session? There are a number of organisations that offer free coaching which may be able to help you reframe the situation and make it easier for you to move on.

Of course it is. What is not normal is your in-laws behaviour. I'd go no contact too. If your DH wants to continue taking his parents to them, so be it. But I'd definitely stay out of these visits.

I'm afraid you have set your sights on an ideal "family" set up the way you want it, but it doesn't work like that. We all have choices and different people want different family relationships, which can be equally valid. Your BIL & SIL obviously don't want the same relationship with you, that you expect. Give them and yourself some space, it is not healthy to obsess about a relationship like this. Focus on making friends yourself and helping your child to do the same.
Whilst it's great you still spend time with your MIL & FIL there is no need for your DH to operate a taxi service to facilitate meetings between them and his sister. They seem to have made it obvious they don't want much contact with the rest of the family, so leave them to make their own arrangements.

Well, fortunately your child has a father who can maintain contact with his and his child's family, including of course the cousin

Poor poor poor DC.

You're making this all about you.

Hopefully your child will be able to salvage a family relationship with their cousins, notwithstanding your wrecking ball approach to family.

it's not all about you

I think the adult thing to do would be to ask them if there is a problem and state the numerous times they have refused to interact , including the party. At least it will be put in the open.,

Excluding your child from the birthday party was only the most recent instance of their deliberately preventing the two cousins from spending time together.

Except they were obviously meeting up at the time!

Not wanting their child to stay, holiday or have a day out with Op I don't think is unreasonable.

I’m so sorry @Pouticel. I can feel your pain as the thread has progressed. This is clearly another let down in a long line of let downs and struggles with friendships / relationships, rather than you having a meltdown over one incident. I think we can accept our own pain and hardships but it’s so much harder when we see the same happening to our kids.

Your SIL is what she is and I doubt she’ll change. I think you need to decide pragmatically whether it’s better for your daughter to have a superficial relationship with her cousin, or none at all. Personally I’d go for the former and try to partially mend bridges, but I know you may not feel able to do that.

Maybe for now focus on your little family unit, and the love that you can all give each other. For what it’s worth I was an only child who was very happy with my own company and that of my parents.

I disagree. OPs thread is over 30 pages deep. She has had ample opportunity to vent and instead of taking on board any of the sound advice given in this thread, she is sounding increasingly unhinged and immature in her responses.

As is often the case, first poster succinctly nails it.

I'm joining this conversation very late! But I don't think you're behaving unreasonably. Excluding your child from the birthday party was only the most recent instance of their deliberately preventing the two cousins from spending time together. And clearly SIL and BIL are disinclined from providing explanations as to why it's never convenient to schedule playdates. Just do what you intuitively feel is right. It's completely reasonable for you to stop contact with SIL and BIL, if you feel that's what is needed now. If DH disagrees, he can be the one to initiate contact and facilitate meetings between DC.