To have nothing further to do with them?

Their child probably wanted school friends there and they felt like your child would be the only one who didn't know anybody.

Did you have a rough childhood? Just an idea but I have an over reaction to being rejected (or my children being rejected) too. I have had to work on it over the years. When they were young, it felt so overwhelming when they were left out and I felt so responsible, as I felt I wasn't good enough either. I'm now early 50s and my children are older teens, so it's much better and I've learnt to live and let live.

Overreaction and now you have possibly fully terminated any possibility of your DC having a relationship with them in the future, I think your own insecurities have gotten the better of you and have a lot to do with this behaviour

Maybe your DC and her cousin wouldn’t have been best friends and featured heavily in each others lives but it sounded like they were at least friends and enjoyed each others.company, you should have accepted this I think

The way you speak about her, i'm not surprised she has picked up on your feelings and wants nothing to do with it all. My DP's sister is not a 'bonus' sister, I already have two who are quite enough kerfuffle! She's ok, we speak when needed, e.g. birthdays, Xmas etc, planning things, as the men are rubbish, I can stand an evening in the pub with her but she's not even a friend and I'm sure she thinks of me the same way. We can get along as we're adults but we didn't and wouldn't choose each other.

And that is fine for both of us.

You’re being really intense. Everyone has their own lives going on. Why does it all have to be all or nothing? We can love our family and not be in each others pockets. I’m closer to my family but if we didn’t have much in common or they were draining I probably wouldn’t spend as much time with them. I’d still love them though.

She was never your sister. That's where you went wrong at the start, with unreasonable expectations. You've cut off your now family, so why is this family avoiding you such an issue?

How often would you like to see them? My brother and his family live 2 hours away and we see each other every 1-2 months. I would have preferred more but it is too far.

I don't think it's your place to sit in judgement on what other people do with their family just because it doesn't fit into your rigid set idea of what families should do and/or look like.

And yes I do care an awful lot more about my friends because they have been there for me at the best and worse times or my life unlike some people who are family only because we share a bloodline but have nothing in common and don't even really know or like each other all that much.

Also comparison is the thief of joy.

so by that view my father who ran off with another woman 10 years ago, never bothered to contact me, and doesnt even know my daughters full name.

he didnt actually do anything physically wrong to me, ever. just decided to leave my mum. in fact he was actually a fanatstic dad growing up. just decided to dip out my life.

im still supposed to love and like him? just because hes my dad?

no. just because someone is 'family' doesnt mean theyre owed anything.

Sorry you are having a tough time OP. I note you mentioned that you currently don’t have a job due to breast cancer treatment but that you hope to start working again soon. Do you think your attitude to the importance of family connections has been coloured by your cancer diagnosis or have you always felt this way?

ETA - just noticed you mention MIL has cancer. Did I misinterpret your earlier comment about giving up work?

Sorry OP but I think you sound very intense. I can completely understand that at 7 a child will be inviting friends they see regularly. It is really complex adding a child into the mix who only know the birthday child. 45 mins away is not like being just round the corner where you may have friends in common. I understand your view that parties are not something you can afford - but this also means there is no reciprocation if your child has been invited before. There are no rules about that - but maybe the little cousin has noticed. You are clearly really sensitive about feeling left out - and maybe you need to explore this with a counsellor so you don’t pass these feelings down to your DC.
Subtle distancing on the back of your disappointment would be reasonable - but it sounds as though you have been really dramatic and this will just make future interactions ( which are inevitable) much more difficult.

Sleep on it and then discuss with DH.

I led a bit of a lonely existence with with my dc tbh always focused on others sharing days out together used to make me depressed and I wasn't outgoing at all which never helped but I'm proud of what my ds is now so don't worry op

What does 'supposed to' mean here? And why are you supposed to? You don't love yours, as you've said. So why should your DP's love you and your child?

Some people are not nice people. The families of these unpleasant people don't have to tolerate them.

If they are so awful why were you trying to force a relationship with them? 😵‍💫 or are they just awful because they won’t support the relationship you want?

I'd play it down now op stop trying don't look desperate it's not a good look for you or your dc leave them be if they visit and the cousins play together great but if not then so be it families can be very overrated never expect much and you can't be hurt.

You're contradicting yourself.

You're very blinkered aren't you? Not all families can be close physically, meaning practically they can't help each other out with stuff like babysitting. Doesn't mean they're far apart emotionally.

why do i need to see my mum constantly? im a grown up, i dont need to hold her hand every day.
at what point did i ever say im not arsed about my family? or that i give more effort and time to my friends? re-read my post OP.

for your information; i dont actually have any friends, i dont leave the house to go and spend time with anyone.

as a grown up, my priority is my DP and my 2 DC.
yes i have other family like my mum, but my main priority is my household.

stop trying to force friendships between family just because thats how you see things should be.

like the example of your neighbours; im sure thats lovely for them, if that is what they both want. but not everyone wants that.

clearly your inlaws dont want to live like that. just because you dont agree, doesnt mean that its not a 'proper family'.

just because i dont see my own mother very much doesnt mean were not a proper family. i know i could call her at any moment and she'd drop what shes doing and be here. That, to me, is a proper family. not constant contact.

familys come in all different shapes, sizes and set ups. what works for someone elses family may well not work for you. unfortunately unless people are on the same page in regards to level of contact, these sort of disagreements happen.

You’ve really got used to your own DH not considering you. He leaves you alone on Boxing Day every year. He doesn’t sound a whole lot better than his sister really.