To have nothing further to do with them?

I don't understand the other posters? I'd be furious too and probably would take the same action and said if their kid didn't like mine to just say it so you can kinda try to cool your son off from them. What they've done is really mean, espythe party thing. We always prioritise family for parties no matter how many other kids are going to be invited.

@Pouticel do you all live close together?

How far is it to travel to your PIL and your BIL/SIL?

I think you didnt take the hint when they refused play dates and sleepovers.

My kids have parties for school friends. Its a bit of a nightmare to mix school friends, other friends and family - kids feeling left out, dc then between different groups at party so we stuck to school friends for parties only.

OP your posts are very extreme. Have you voiced your belief that you want your daughter to have a relationship with her cousin because without her she will be alone with no family? Because that is alarming.

your daughter will make her own way in this world, she might marry and have children, she might build a close network of like minded friends, she might be comfortable in her own company.

but placing so much pressure on a relationship between two seven year old is suffocating. Yes it would be lovely if they kept in touch when they are older. But expecting them to be each others only company at Christmas after all their parents are gone is a huge and worrying leap. For many reasons.

There are obviously many layers to this. You and your child are ND and you feel socially excluded at school, and from school mums.
You are also an only child and if I understand correctly you have struggled to make friends in life.
So I assume that when you and your SIL had kids at the same time you saw this as an opportunity. The rejection you now feel for you and your child is extreme. They don't owe anyone their friendship or their time. DH and his sister can be in touch without their children needing to be close as well.
You are trying to future proof your child's life, but this is not the way to go about it. He will, as a neurodiverse person have to find his own feet and make his own way in the world, and find his own peers.
Blocking them, going upstairs and sulking is not setting the right example for your son for the future in how to navigate difficult social situations.

I think it is quite usual for children or teenagers to have a party with friends and a separate celebration with family?

Shocked at the amount of people defending this. It’s incredibly bad mannered of them. That said, I wouldn’t have stealth blocked them and sat upstairs, I’d have confronted them there and then.

It’s also not a difficult concept to ASK op about the party instead of just assuming and piling on her.

@Pouticel what kind of party was it?

@Rosscameasdoody
Perhaps they told their DC not to say anything because they knew OP would overreact?

We only have OP's side of events but it's pretty clear how she responded was disproportionate.
Maybe this is death by a thousand cuts for OP and she just lost it as it has built up over time.
It is clear that she is overly invested in this cousin relationship when the feelings are obviously not reciprocated

many parties have limited numbers, or a set number, you invite one cousin means you can't invite a friend. It's not a difficult concept.

They ARE having a little family party with cousins and uncle and auntie, how is that excluding anyone?

At first I thought you were being a little bit unreasonable..but after seeing the rest of your posts.....fuck em. Nasty pair of wankers, tell them to amend their will and fuck off.

you expect the cousin to invite YOUR child instead of a friend?

OP never said she expected that a child be excluded, so stop piling on her with lies.

She’s had a realisation that SIL and BIL don’t want her in their lives beyond the bare minimum and she’s dealing with it by withdrawing. She hasn’t screamed or shouted at anyone, but she is allowed to be hurt and to withdraw.

I may be one of the very few here, but I agree with you 100%, OP.
If what you say is true, and I have no doubts that it is, then to hell with them. Life is too short to spend any of it appeasing assholes.

And here's to you. 🙃

I agree with other posters that you're taking this way too personally and massively over reacting by storming off and sitting upstairs having a pity party whilst blocking everyone on SM.

It's very much exhausting, immature behaviour.

I say this as an ND Mum with an ND child.

It wouldn't have hurt you to have openly said 'Oh, that's a shame. Was there are reason why DC couldn't have attended' and they may well have given a valid reason, or a bullshit one, but either way you would have dealt with it like an adult.

Whether you like it or not, there are sometimes valid reason for controlling numbers at kids parties, especially if held at eg a soft play centre or event space. We have certainly had parties in the past with a stringent number control (eg Nerf war, go-carting etc).

I never once invited a cousin or family member to DS's school friend parties, as is my right. Why? Because a couple of the school boys were proper little nob heads and could be vile. It was 'the done thing' to invite all of the boys in his primary class to all parties and boy did we know about it! At no point did I have to justify this to anyone, though.

Parties absolutely do not need to cost £300 and you don't have to hire anywhere.

You seem to have very fixed ideas about how things work and how others should be behave. You'd be a lot happier if you accepted that others do not need to do what you expect them to do and move on.

Your reaction to this is going to make your DC feel worse. You could have tried to brush it off and then make up a bullshit reason to spare their hurt but here you are, in the bedroom, throwing toys.

All this storming around, stamping feet and sulking will not make people more likely to want to spend time with you.

Have you ever tried to squeeze in next to a larger person when there's a fuck off car seat? I couldn't fit them in my car

OP, you sound absolutely exhausting and having a full on tantrum doesn't help anyone.

You meant well, but you sound very.. "full on". No wonder they don't want their kid to go on holiday with you. You are being massively U to sulk about it. You offer, they decline, offer again in a few years when the kids are older.

YOU are ok with not having money for a party, but you expect the cousin to invite YOUR child instead of a friend?

Hasn't it occur to you that they are having a "family party" with a little cake -that's for you and the cousins

and a "friends" party, with .. friends.

You are so unreasonable and entitled to expect your child to be part of all the parties, it doesn't work like that.

The only one you are punishing with your unreasonable behaviour and over-reaction is your own child. Become an adult and stop the drama, or you will destroy all the relationship.

The only reason why your child won't have a cousin in his life is YOU I am afraid.

I was totally on your side until you said you wen't nuclear.
I wondering if your own reactions to things are part of the reason that they have distanced themselves.

Sounds like everyone has got very comfortable with excluding you.

I don’t think it’s good for your child to see that they have family meet ups with everyone except mummy.

SIL can travel to PIL on Boxing Day from now on. Say you’re happy to travel to PIL but they can’t take DC to SIL’s anymore on Boxing Day or any other day.

For me personally the party situation wouldnt be an issue. The boxing day situation very much would be an issue.

You are hurt for your child and that is completely understandable. Your dh should be too and for me therein lies the problem. He'd rather keep the peace than speak to them about it. It doesn't have to be an all guns blazing argument but he could have at least commented that it was a shame your ds wasn't invited as he would have liked to have seen his cousin on his party.

You have acted quite childish by going off in a huff and actually to most you will look like the unreasonable one casuing 'drama'. When in actual fact you are just at the end of your tether. It would have been better to ask why your dc wasn't invited and if there is an issue what is it.

It is also unreasonable of your dh to keep acting like a wet blanket. I would be angry at him too.

You can’t use autism as an excuse for this, you’re behaving totally irrationally!!

I can completely see why you’ve had this reaction, as it certainly feels like there is an injustice against your child.

I wonder if you can opt out in a bit more of a neutral way - yes they can call round and bring pil and cake, no you aren’t going out of your way to host. It’s evident that sil is selfish and going to act in her own interests - what you can control is your reaction or not to it. I bet it’s in you/DH to manage the PiLs too.

Kindly - it also sounds like you are lonely/ feel excluded by others and are very hurt that sil who has a natural reason to include you as family simply doesn’t. She is in charge of her own decisions, just as you are. I wonder if your energy would better be invested finding friends or hobbies for yourself (and your child)?

OP it's honestly not that deep. No need to block anyone. Archive the family chat. Post sparingly. Being able to react with an emoji has been a proper God send. Live your life. No stress.

It's not your DC. It's you.
Stop the am-dram and grow up.