To have nothing further to do with them?

Your child wasn't invited to a party. That's not bullying. You don't know why she wasn't invited. It's possibly due to your inability to respect SIL's no when it comes to her child.

You've been badgering the parents for months with unreasonable requests like taking their 7 year old for the summer and taking her on a holiday (when you say you can't even afford to have a birthday party for your daughter). You had a flounce with them in your house and went upstairs rather than speaking with them and be civil. Your overreactive behaviour alienated them even more, most likely.

This is some very black and white thinking you’ve got going on OP

Sounds like they do wants the children to have a relationship - they have literally come to see you. They just don’t want the intensity you’re looking g for. You risk cutting off your nose to spite your face here.

It really isn't awful. It is very, very usual. They have had a school event and a family event. Sounds perfect.

But have you actually spoken to them at all? You seem to have gone from zero to nuclear in one afternoon.

wouldn’t it have been better to just sit down with them and say you d noticed they’ve been pulling away and now this party issue. Why is that?

i suspect they find you a bit suffocating and you’d need for the cousins to be close like siblings isn’t something they enjoy.

The fact that you start off with the ‘only family’ comment shows a deep level of possessiveness. Maybe they don’t like that. I had a situation with my MIL trying to create closeness between my DC and my SIL’s kids on the basis that then they could ‘share’ things when they are older. Of course the reality is it would be my kids doing the sharing (ie: property gifted to them etc). I backed straight off. The kids see each other of course but I am not setting it up so anyone is reliant on my children

My DD (now almost 40) is an only child, come Christmas she would much rather be on her own than with lots of people. Her partner is from a large family with various small children when they all get together,... His family understand that DD is overwhelmed by so many people and bustle and do not take offence that she prefers to Christmas with her pets or myself, DD joins them for mince pies then leaves them in peace for meal time

I'm using this as a example that different people want different things but most are adult enough to find a compromise.

Throwing a strop then sulking in a bedroom like Kevin the teenager is not the way an adult should behave. If you were my daughter I'd be thoroughly ashamed of you.

Think YABU but so are they when they made their child keep it a secret and expected them to do so. Don’t know many 7yo who can keep a secret. If they do have an issue with you, they could have gone through your DH.

I’d leave it because it is nothing but wasted energy and hurt feelings when they’ve shown they are just not keen and you can’t make them that way. Relationships are a two way street and just because they’re family and only cousin to your dc doesn’t mean they want the same level of relationship that you desire and you have to accept that and either take what can be offered or step back and leave it to being polite and cordial when they are around while not bending over backwards or trying to force something.

If you genuinely don't why they are avoiding you, and if your relationship with the PIL is ok, maybe you or DH could try approaching the PIL to see whether there is anything you could do to help foster a better family relationship all round.

You’re projecting your experience onto your child. Massively. No one is bullying or excluding your child - my kids don’t even have each other at their parties much less cousins! Nor would I allow my siblings or sibling in laws to take my child away on holiday.

I’m sorry you didn’t enjoy being an only child, but there’s no saying your daughter will have the same experience. And you can’t keep trying to turn her cousin into some kind of pseudo sibling.

I think you’re getting a bit of a hard time here. It’s not the party that’s upsetting you, it’s the gradual distancing over time and the bigger worry that your DD might grow up without family connections. That completely explains why you’re feeling so upset.

I agree it’s important to try to keep that cousin connection open, so if the girls want to maintain a relationship into adulthood, the foundation is there. But at the end of the day, you can’t make the parents reciprocate. I’d just keep it friendly and continue inviting them over.. eventually, they might either stop making excuses or be honest about what’s really going on.

But you have money to take the cousin on holiday?

odd.

@Pouticel "I’m so sad for DC that there won’t be any cousin relationship, especially because there’s no other family."

I do understand this OP being in a similar position but you can't force love and friendship. Deep down I'm sure you know that. Perhaps the cousin isn't quite as keen as you think they are. A child isn't going to have the complex emotions about lonely Christmases in old age that you're projecting. To be perfectly honest your intensity to cultivate this closeness is actually almost alarming, or at least certainly off putting. You've been texting the parents to arrange holidays, days out, visits - all sorts. You're wearing your neediness on your sleeve and (rightly or wrongly) people don't like it.

Why do you think this exclusionary behaviour keeps happening?

OP, despite the mostly YABU replies, the voting currently stands at 57% YABU - 43% YANBU. I understand how you're feeling and, while I would not have gone nuclear (perhaps due to lack of balls), I would have been very upset. I don't understand who these parents are who could watch their child so roundly and thoughtlessly rejected, and remain temperate and equanimous. Perhaps they're the same parents who head for The Hague the second the year 1 class teacher tells off little Johnny. Who knows, it takes all sorts.

I hope you can move past the hurt soon, and see that you and your DH are absolutely enough for your DC, and you don't need to beg for the crumbs of unwilling family members. You will make your little family work. All the best.

Total over reaction.

it’s quite normal to just focus on school friends as they get older.

and there’s zero need to end the relations between cousins over this.

you are being a total drama llama

I too suspect it's about you rather than your child, who is collateral damage but family don't have to spend time together, it's not mandatory. The more you try to force it the more they will withdraw.

Exactly this. Unless someone is extremely introverted and avoids all social events, school, or university, the idea of inevitably spending every Christmas entirely alone is a bit unrealistic. Your child could very well be married with their own family before you’re even gone!

I have an only child who doesn’t have close cousins, and I’ve never worried about this. After all, many people never have children or a partner, and they still build meaningful relationships. My only child is by choice - but it sounds like you’re feeling sensitive about having an only child (which could be understandable; I don’t know what you’ve been through).

That said, you can’t force friendships. Instead of reacting so strongly, perhaps a more constructive approach would have been to simply ask if there was a problem?! Did you ever reach out before blocking them and ‘going nuclear’ ??

They will be ok, they are young and won't know any different.

My dad had a very complex and complicated relationship with his siblings and as a result all the cousins are fairly close to some degree or another except for my siblings and I who only ever saw them every few years at weddings and whatnot and now I would struggle to pick some out of a police lineup and them me.

It's honestly fine because it is what it is. No I don't have that close knit gang of cousins that everyone on MN apparently has but I have it with friends instead. And that's even better because we've chosen one another.

I dont blame for being annoyed. It's very tactless for a child to say this about a secret party and also very bad for the parents to put their child in this situation and ask them to keep secrets.

Do your BIL and SIL have more than one child @Pouticel? If so, do you make sure the sibling is included or is your focus always on forging a friendship between the seven-year-olds?

This isn’t really bullying though. It is just different expectations of family relationships. I think you need to be very careful not to project these feelings onto your child. They’ve chosen to celebrate right you today so they clearly do want a relationship of some sort.
Storming out is really bad example to set your child.

Listen to your DH. You’ve gone nuclear and ended the relationship. They didn’t, they’ve not wanted you to take their only child with you to keep yours company. They’ve invited their DC’s school friends to their party. Neither of which is wrong.
You’re projecting your issues here and it’s your DC who’s lost out. It’s pretty clear why your in laws have stepped back. You’re far too much. Why would they want someone who behaves like you do around their child?