To have nothing further to do with them?

This is really sad. And what a lot of pressure to put on a 7 year old to tell them to keep the party secret. I love that the cousin blurted it out and also revealed that it was supposed to be a secret! I understsnd why your DC is upset and why you are too. I think you should be honest with them and tell them you are disappointed. I think that is better than storming off. When you do that you give them ammunition to confirm that you are awful and should not have been invited. Don’t give them that ammunition.

and I adore my nieces and nephews but my DC only invite their own schoolfriends to parties. Otherwise it gets too complicated. We dont even do family birthdays so they
re doing more than I would do.

Sound exhausting

You sound very hard work, like you're working so hard to have a relationship with BIL and SIL and their child for your child's sake, that it's coming across as very intense and I'd be willing to bet that's what's causing them to back off. They are entitled to have whatever relationship they choose with you, and you're entitled to be a little disappointed but should just accept it and focus on making lots of close friends for your child instead of fixating on family members that you can't control.

Your anger and pain comes through loud and clear @Pouticel, and I understand it. You’ve clearly made a lot more effort than them for a long time now. I think they’ve been rude and thoughtless.

However.

I think right now you’re also reacting out of all sorts of things that aren’t on them- your childhood, your friendships, your underlying fear of rejection. Those will be colouring the intensity of your feelings here.

So I guess i’m saying just be aware of those, take a breath, and don’t shoot yourself or your child in the foot.

Can I ask does your child have invites to parties at their school because inviting cousins at this age is rare and I have always felt sorry for both on the odd occasions I have seen it as they are often left out of the class dynamics and leaves the birthday child struggling to accommodate everyone.

the fact they had to lie is I think because they didn’t want you to react like this, they don’t want you to take their child away or on days out and that is fair enough

to be honest I suspect they may well be relieved this has happened.

i am an only child, who cousins are either in Australia or 23 years younger than me and my two don’t have cousins (DH sister no kids) and small Cheistmases are just fine by me!

Maybe they are busy on weekends. Often a lot of clubs happen on Saturdays, then if they do something like football they then have matches.
I think you are being completely OTT about this.
We generally only see my niece every 3-4 months despite them only living 30 mins away!
You seem to have an unhealthy obsession that they should be spending time with your child.
Maybe they are miffed that the in laws aren't arranging to visit them more often. But then not everyone is fussed about grandchildren and maybe PIL are happy with current arrangements.
What about family on the other side - your BILs family?

They are celebrating the birthday with you, as family. I don't get why you want more than that. If they didn't do that then yes they would be excluding you, but the fact they have done something separately for family shows they are doing things with you.

If that fussed when it's your child's birthday why don't you actually organise something. As many others have said it doesn't have to be that expensive. We did bowling for 6 kids for £120, 2 games and food.
You need to focus on your social skills as maybe this is what prevents you making friends from the way you come across.

Sooo (and I do mean this with kindness)… I wonder if your response to this (storming upstairs) explains their distancing. When people feel that they have to keep connected, some feel trapped and pull away. I also feel rejection strongly - I think for some people it can feel devastating, even physically painful. What I have learnt over the years is to play it cool in response to it; step back a touch but remain friendly.
If I were you (and if your DD and her cousin really get on well), I would take this lightly; make the most of it when you see them and don’t press too hard for a meet when you don’t. The problem with responding with fury as you are (which I’ve felt too) is that you’re showing your DD that a). This is a massive deal and b). You respond to rejection by telling the other (through actions) to fuck off! I think a better way - if she is upset - is to tell her that sometimes kids choose other friends for sooo many reasons and in fact it might be their parents choices! She (as we all do) will face rejection in her life and this is your opportunity to show her how to manage it in a measured way.

I have two teenage girls so have been to many birthday parties over the years and would say past toddler age when they have started school it’s very unusual for family members to be invited to parties. I would say the norm is to have a party for school friends then a tea party at home for family (which is what has happened in your case).

You are also massively projecting your priorities and worries onto other people, which is not fair. They may not be concerned about their DC having little family. They may hope that their DC will build their own network of family and friends in the future. You’re putting massive pressure on the relationship by basically saying that they will only have each other.

If it’s not unusual for people to reject you, kindly, you need to reflect on how you’re interacting with people.

I have some family that I am taking the intentional approach with but it's a mutual thing, it can't be one sided. The adults have to like each other to it to have a chance of working and even then it's only a chance.

I think they just don't like you very much. And that's totally allowed. I have family members I see once a year but would not go out of my way to see them otherwise.

Am I not allowed to hang out with people I like? They didn't marry you, your DH did. He is the only one obligated to spend time with you.

We are the same.
Our families are getting smaller, from growing up with 4 siblings, to all having 1 or 2, we nurture the relationship between the cousins, the cousins are very close on my side, and DH side.

I think to call the OP dramatic etc is a bit unfair. She had the best interests of the children at heart, extended the hand of friendship and has been rejected a fair few times, at odds from previous behaviour. It think the party would've hurt my feelings too as it was at the end of the other attempts. The cousins family could've handled things much better imo, even if they did want to pull away.

I don’t think weird at all. I have a cousin who is an only child and who has lost both her parents. I remember growing up our relationship was very much nurtured exactly due to the fact that she had no siblings, and her parents I guess wanted to ensure that when they were gone, there would be family support there if needed. And that’s what’s happened. Of course she has a partner now and has friends, but she very much values the fact that she has family connections on her side of the family.

I do think it's upsetting that her aunty has invited her niece to daughters party .. I'd wonder why myself.
Encourage your daughter to have her friends and don't try and force it anymore x

I agree backing off is probably the way to go as they are obviously not interested in facilitating a relationship between the two cousins or indeed yourself. I personally would not be happy if your DH and DC disappears off every Boxing Day leaving you alone. I would be making your BIL and SIL facilitate getting PILs over to them. Your DH does not sound like he is bothered about his sister snubbing you and DC. Eventually your DC will notice and won't want to go. It is awful if they are excluding her because she is ND and don't sound nice people anyway.

Perhaps they are actually trying to avoid the PIL and due to your proximity to them, it is a consequence of that? It seems odd that they don’t see or visit them.

Failing that, can’t your DH just find out what is going on with his sibling?

What if the answer is as simple as it was a class party. It’s entirely normal to have a class party & a family party/cake which they are currently having!

As the 7 year old moves further into primary school friends become a bigger part of their life, entirely normal & ok.

@Pouticel going forward invite your daughter's friends to tea, let her build relationships there.

But you say they're all at yours today to celebrate the grandchild's birthday so clearly haven't been excluded?

Can I ask @Pouticel how your son is in new situations with new people? Autism obviously presents differently in different people so trying to understand how he’d be at a loud crowded kids party?

There are some situations where I just wouldn’t take my children. I am able to judge quite well what my children can cope with.

My children are a much poorer judges and I wonder if perhaps you are not open to the possibility that some environments might not be great for your child?

HOWEVER a conversation should be had, not hiding and asking children to hide their party from family.

If your son attends parties etc frequently without upset or incident then it seems like a really unkind choice.

I am very open and able to say ‘sorry - that’s not suitable for Littlegoat or Babygoat but have a brilliant time and we’ll do something else soon’. Are you tuned in to the things your child can cope with and open to conversations like this?

Not quite the same but I celebrate my bdays with my DO & DD - and my friends. They’re my chosen family & I afore them & vice versa.
my mom sends an ecard. Blood relatives send text messages. But my party/dinner/celebration is w my friends - friends can be just as valued/more so than family

I can see both sides of this. My DC is an only child and the cousin relationship is a very important one. And yes, it does seem they are pulling away, and how they've handled the party situation hasn't been great.

But you are cutting off your nose to spite your face here. You and your DH need to talk to them to find out if there's anything you're not aware of. For all you know there could have been an incident between the kids and their DC didn't want yours there, or to see them so much in general. As much as these relationships are important you can't force children to get on or be friends. Their future relationship will likely depend on how they get on as adults and how important they see it, completely independent of you.

BUT deciding they will never ever see each other again because you're done with them is very much a good idea way to ensure they don't have any type of relationship. You can pull away/make less effort without cutting them off completely. I have lots of family I only see every six months or less, that doesn't mean we don't love each other/are there for each other when it counts.

This sounds tough. I know you can only get a snapshot of things here but I understand why you are feeling like this. I have an only child too and am keen for her to have good relationships with her cousins. Its my siblings kids which does make things easier. But I think you can’t force things, just let things evolve. Even if they were best mates now, there’s no guarantee of anything in later life (even if they were siblings rather than cousins).
I should add that I have done parties where I invited my DD’s cousins as well as best friend from nursery and school and other close friends. But felt it didn’t work that well as the kids didn’t all know each other and I think they felt a bit awkward. So we’ve often done parties with school friends and then something separate with cousins or nursery friends etc. just trying to say there wasn’t necessarily any ill intent here. Your child might have felt quite overwhelmed at a party in a hall with lots of kids she didn’t know and where her cousin might have not been able to spend much time with her.
My DD didn’t go to her cousins parties last year and vice versa but we’ve been round for cake and stuff. To me that’s the real celebration as parties are stressful and this is being with family, the kids are running round and we’re just chatting and eating bits and bobs without it being an extravaganza. I wonder if they may have hid things from you because they were worried about how you’d react as you have a different approach to things.
Re not taking up other invitations, they may just be really busy and it’s just practically easier to do local stuff. I know you’ve offered lots of things but I sometimes don’t accept offers because I’m not sure I can reciprocate and I don’t want to just take. I also am a bit last minute about things and don’t like to plan too much and can feel pressured with invitations- I realise that might sound a bit weird but I just feel overwhelmed with things. I just mean their actions again may not be meant in a negative way.
anyway, just some thoughts to possibly reframe things. Best wishes

I've just spotted this in a previous post -

Once your parents and grandparents are dead, you have to spend Christmas alone and you have nobody. I don’t want that for my DC or theirs.

Wow!

They are perhaps perfectly content with the family relationships that their kid has.

No wonder they have stepped back if you are trying to force your way onto them.