To have nothing further to do with them?

You've said a few times that one parents and grandparents are dead, you have no one left as an only child.

Your child will hopefully grow up and have a family of their own.. children, grandchildren, inlaws etc

An only child can go on to have a large family.

I’m not good at this and it’s a constant struggle trying to navigate what you’re supposed to do. If I screw it up by being me then DC loses the friend.

I think you’re putting far too much pressure on yourself to facilitate friendships for your DD. Children make their own friends, all you need to do is be supportive and if your DD would like to ask someone over to play, say yes and let them get on with it. Don’t stress about whether the playdate is reciprocated, it’s not a big deal ( unless the parent is constantly dumping their child on you while they run errands, for example).

Your DD sounds fine, she has friends at school and she’ll make more. Don’t worry so much. 💐

Why is your DC excluded by others? Is it their behaviour?

Is there a reason your don't have mum friends?

I don't mean to be hurtful.. but if you're always being excluded..it may be time for some self reflection. You seem to be the common denominator.

Don't they play together in school? No one does playdates 'most days' so perhaps your expectations are a bit off. We do see school friends in gymnastics/brownies etc so perhaps get her involved with this type of thing. Working parents can't arrange such frequent things and often want to spend time as a family on weekends. Perhaps their daughters are doing clubs/music/sports etc after school.

I think the sleepovers issue has changed a lot between our generation and now. People are just more cautious especially with girls. This is just what I've noticed from DDs group and I don't take it personally.

I was just thinking.. does SIL's DH have siblings and therefore their child has cousins on his side of the family?

I ask because my DC have cousins on both sides, but aren't close to the paternal cousins.

It could be that she doesn't need her child to have a relationship with your child, as much as you want.

Plus..I go back to the financial gap. If you've never been able to afford a party in 7 years for your child, she may see you guys differently. Some people are a bit more judgemental in that way.

Also it wouldn’t have been months if they were not refusing all contact between the girls for no obvious reason.

Except they haven’t done that, the girls just saw each other today….. you are being hysterical now

Your socio economic groups are quite far apart and that may have something to do with it.

I'm thinking of my family... my kids always had their cousins at birthday parties and vice versa...BUT, we're a very close family.

I'm very close with my sister..6 months would never go by without seeing each other. We speak every day.. or at least 2 days don't pass without us speaking.

I doubt that your husband and his sister are that close and you can't force the cousin relationship.

So I understand that you're upset, but the closeness has to be with the siblings in the first place.

Can I ask if the kids are the same gender?

OP I understand how hurtful it is. I'm (suspected) ASD, my son has ASD, and the pain of desperately wanting them to have friends / close bonds with other kids, and seeing them not materialise, is horrible, especially as you've gone through it yourself and know how crushing it is. I do get it. And with family it must be even harder.

But you do need to deal with it more positively. Yes, you have the right to feel bitter and angry and resentful, but do that in private, away from your daughter. Don't cultivate this "woe is me, everyone hates us" attitude in her. It won't do her any favours. So she's ND - does she know that? Can you explain to her something like "Some kids click with lots of people, others find just a few really good friends. You don’t need to be friends with everyone - you need people who get you”. Or "It’s really sad when someone doesn’t want to be our friend anymore, and it’s okay to feel upset about it. Friendships don’t always last, but that makes space for new ones". Boost her self-esteem. She is a great kid who will find her people eventually. That way you aren't lying to her. But you're reframing it a little. Saying "fuck them, we want nothing to do with them, they're shit people, it's us against the world" might feel righteous at the moment but it won't do your daughter any favours down the line.

It sounds like you and your in-laws had very different expectations of what a family relationship meant, and this resentment has been festering for a while. Let them go, that's fine. You can't force the relationship. But if you go nuclear be aware it might sour the relationships with your PILs.

Why is not seeing each for months what makes it weird? Isn’t it that OP has told us that they don’t like her that it sounds weird rather than the distance between seeing each other?

I agree, a play date every other week is a normal frequency.

keep doing play dates , so long as your DD enjoys them. I’d also suggest Brownies or some other out of school activities so that she can make friends.

focus on little and often opportunities for your DD to make friends, and the party invites will naturally start rolling in.

a cousin 45 minutes away should never have been the primary focus for friendship building. I have an only, and when he was young I just put a lot of effort into hosting play dates and booking really good parties. It’s just what you need to do if they have no siblings

Just to say the friend situation doesn't sound too dire! What are you expecting? Once every couple of weeks is a lot for one child, and if the other parents 'drop and run' so what- you are facilitating your child's friendships not your own right? Some people don't return playdates so much.
Perhaps if you are worried about messing things up just try to be less intense. Let your daughter join some clubs and activities where she can make friends.
I wouldn't send my 7 year old for sleepovers or holidays with my brothers family btw and we are quite close and most of her friends from school are not allowed sleepovers (families we are very friendly with go away with etc) so I don't feel your SIL saying no to this is anyway out of the norm. It's sad by 'going nuclear' you are essentially ruining any chance of a normal cousin relationship in the future because they can't match your expectations.

I don't think it's reasonable requests, especially when they haven't seen each other for months. Someone you haven't seen for months wants you to send your kid to theirs for multiple days, what? That makes no sense. Of course they'll say no.

Inviting cousins/nieces for holidays and to stay is not unreasonable or objectively outside the form. That’s you projecting your own disapproval if OP’s actions on to her in-laws reaction. For all we know the only issue is less about the nature of the invites themselves but more to do with their feelings towards OP.

Yes OP is very intense and not taking the hint but they could also open their mouths and speak up if they want to shut down further requests.

Stop it! Stop it! Please stop it!

For the 10 millionth time, IT'S NOT ABOUT YOU.

You said you asked for her to stay the summer. That's not a few days.

But. A lot of parents don't want their kids doing sleepovers, much less days away from home or holidays away without their parents. I would say that's a norm at that age.

You push when you should back off. Their saying no to invitations is their right as a parent. You're not going to be able to force a relationship. You're going to have to look elsewhere and one way you can do that is encourage your child's interests. Enroll them in a sport. Have them do Brownies. An art class. I supplied stuff for bracelet making and T shirts and stamps and fabric paints so they could make their own t shirt designs for parties. But you're going to have to make an effort.

Is there any chance that your DH sister's husband could be controlling and limiting contact between her and her family? Sounds like a horrible situation, especially when she has very little contact with her own parents

Do you think you might be projecting your own insecurities about being an only child, and trying to force a sibling relationship between cousins? Do you think that could be what's making hour BIL and SIL distance themselves?

For the record I'm an only child. My family for the most part is my child and my husband and I'm okay with that. I don't see the point of having histrionics about when everyone around me is dead. There are plenty of people who don't talk to their siblings so it's not like I was deprived of a guaranteed close relationship with the siblings my mum chose not to give me

I can see why you’re upset. I remember when my sister’s child stopped inviting my child to their party. They were a similar age. I now accept that this is NORMAL in a lot of families, they simply move in different friendship circles from that age.

I’m sorry you had a lonely childhood. With kindness, you’re trying so hard to make this not be the case for your daughter (understandably) but you have gone at it too hard, like taking a sledgehammer to crack a nut.

Pls be careful your child doesn’t hear you complaining about her not being invited or you’ll seriously damage her self-esteem by projecting your own insecurities & sorrows onto her which could possibly damage your own relationship with your daughter as she gets older.

There’s still a chance you could return to the group. Explain your history of feeling lonely as a child and why that made you desperately want things to be different. From their point of view, they still had a celebration with your daughter so won’t understand why you’re sulking.

I’m not good at this and it’s a constant struggle trying to navigate what you’re supposed to do. If I screw it up by being me then DC loses the friend.

Well then, good for you. Yes, it is a struggle. You are probably meeting people who are invisibly struggling too. Most of us are, one way or another. (I have to walk with a stick-I've had to since I was 21. I was the one who looked like a granny at the school gates.)
It doesn't matter about us. Put on an act. Pretend you are in a foreign country, with an unknown set of rules. Don't screw it up. If you do, iron it flat and start again. You are not alone in your feelings. One day, you'll meet another person more scared than you, and you will have to do the psyching up to them.

You have to do things for your DC that you wouldn't do for yourself. So does your DH. So do we all. Good luck. Be brave. Fake it till you make it, and remember loads of us are doing exactly the same.

OP I think you should just ask your in-laws directly why they keep on turning down invitations.

You, your husband and your daughter are your family.
and your parents

for your husband, it is you and your daughter
and his sister that are his family
and his parents

his sister is only family to you by marriage, not blood.
your husband's niece is family to him, once removed by blood

his sister's child is only family to you by marriage, and once removed i.e. a different generation.

You have behaved very badly today whilst entertaining / hosting his family, then you threw a strop by all this removing on social media and hiding upstairs in a bedroom.