To cancel DD’s birthday party because I know her dad will ruin it?

If he must come, ignore him. Tell him you’re not able to cater for extra guests; no food or party bags. Let them stand about looking mardy.

Just let them come and stand awkwardly on the sidelines.

I think making the best of a tricky situation would be to allow Dad, GF and grandparents to come but I would draw the line at letting the GF’s younger kids come. They will change the dynamic and would do even if they were full siblings. It’s fine for your DD to have the day just with friends her own age.

I wouldn’t have thought it would matter about capacity with the adults so much? You might just have to tell them there will be nowhere to sit but they are welcome to come.

It’s very hard OP and I disagree with what he is trying to do but perhaps in the future you need to be honest with your DD if she wants things on specific days that fall on her dads days. If you’d have had the party the weekend before/after this situation would be so much easier to avoid. She’s understandably upset now because what she was expecting isn’t happening, whereas if she’d have had this expectation managed from the start then I doubt she’d be so upset.

exactly. He sounds like an involved Dad. You sound controlling - and your daughter is parroting your behaviour / reaction. And yes I also Co parent.

I think you’ve learned a good lesson here about how to avoid this in future.

personality I’d say him and his parents can come if they really want to as it’s not really fair for you and your mum to host on his weekend. Then he can bring her back to his afterwards. The random tiny children aren’t invited, that’s not a thing - my kids have almost never even gone to each other’s parties as they’re for friends. In fact, I don’t think my husband has even been at the vast majority of the parties either - he usually keeps the other child home with him and I host on my own.

I understand why you booked it but I think having your mum there and it being in his weekend and him assuming every activity is a big family affair is confusing something that should be simple.

That won’t work, I presume he will just turn up anyway with his entourage, knowing that OP won’t be able to make him leave without causing a scene

The problem is, the divorce politics are all playing into this. If we remove that... any 10yo girl having a birthday party with friends likely wouldn't want grandparents et al tagging along. I'm amazed your ex can't see why this is inappropriate. Especially the gf's younger kids too.

I think you need to tell him straight- DD is getting too old to have the whole family tagging on to a party with her friends.

He's unreasonable to try and piggy back his entire family into the event to make it look like he's been part of organising something amazing for her. If his family genuinely want to see her for her birthday then he should arrange a similar thing or family meal etc.

That said, if it's his weekend then it's a bit messy, think it could have been communicated better on both sides.

The word you need here OP is ‘no’. No, he can’t come, his parents can’t come and his girlfriend and her children can’t come. No. This is a party you are organising and paying for and he agreed to give you the time to do this. There isn’t an issue with him not being invited to the party you have organised and paid for, because obviously he can be at the one HE arranges for her, where his parents and girlfriend can also come and anyone else he and DD agree. You will not be at a party he organises either. Fair’s fair.
Tell your DD sorry but you can’t cancel because you have already paid for it. You can cancel if she insists, but there will be no alternative treat as the money was spent on the party. She is 10 she needs to learn that reality. Hopefully not a problem once you have told her dad ‘no’.
Going forwards, arrange things on your time only to avoid this. If that means DD needs a party organised on dad’s time, tell her to speak to her dad. There is nothing you can do as she will not be with you at that time. Then talk about what you will arrange during your time.

The hall has a capacity. That's it. End of story. There's not space for everyone that he wants to bring. He can come, he can bring 1 other adult (same as you). He cannot bring extra people and they will be refused entry on the day due to the capacity limits

Clearly didn't check or discuss the most basic thing for a party: who's coming. Date, arrangements for the rest of the day, yes. Read the OP and there's a lot of assuming going on. Probably on both sides tbh, looks like ex assumed OP would do the planning and he'd be there same as many not-ex husbands/fathers do...🙄.

He'll be thinking he can show off to his parents and girlfriend what a smashing dad he is (yeah just rocking up to a party he's not organised or paid for but happy to stand there and take some credit!)

He's likely already told the girlfriend it's all fine, so she's thinking woohoo free food and entertainment for my kids.

And that all matters more to him than how his daughter feels, and he'd rather dismiss how she feels. He says she'll be fine but what he really means is she'll just have get over it. On her birthday. What a knob.

The hall must be very small to only accommodate that number however I agree with your daughter, bringing the GF and her younger children is really not on, your ex-H must be devoid of any imagination if he can't see why that would upset his daughter.

She did check with him beforehand

I think you messed up by organizing a party for her without including her other parent. Had you had a conversation with him first, this would all have been aired before then.

Anyway at this point you need to dial it right down for her. She's only 10. Party should go ahead, children should come, ex should come as should partner and her children and his parents. The table will be set up for 11, adults will just skulk around the edges and maybe help hand stuff around and slice cake. It's a kids' birthday party, it'll be fine. Your focus is on your daughter, not this side drama. Both parents and as many grandparents as possible should be there to sing happy birthday, smile as she blows out her candles, remind her to say thank you for her gifts.

If the 4 and 7 yo tip the numbers over the maximum allowed, you'll have to tell your DP this. They and their mum will have to stay away - and sorry, but I think any accusation that you've excluded them is kinda your fault because you excluded the actual dad.

This should all have been flushed out before hand, and because it wasn't you're here. You'll know for next year. You're not her only parent.

I've had similar issues to this. Id tell him his parents are welcome if they want to come and help but that you are at capacity for children so your gf and her kids should meet him and DD for their family celebration after the party. If he tries to argue just tell him you have been told very clearly that the party is already at capacity and they are not invited, they were never invited. They can all do their own thing after the party. The only way to deal with this is to be the bad guy to take flack off your daughter and stick very clearly to the boundaries you have already set. He made this issue by randomly inviting others to a party that he hadn't planned or paid for.

You sound as if you think DD is more your child than his. Why did you book it on his weekend? You should have booked it on your own time with her. It's his time and I think you are being very unfair ...at the very least you should be welcoming him , his gf, grandparents since you have overstepped and very arrogantly decided to arrange a party in his time.

Someone give this poster a gold medal. This is absolutely spot on. OP frame it and put it next to your bathroom mirror.

IMO the priority would be avoiding the stepsiblings unless DD is really keen to avoid dad being there altogether, because adding extra children will change the mix of the party, but I would not cancel the party, it seems like a shame. If the compromise for it not being cancelled means that your ex and his parents come, I think that is less of an issue unless DD is adamant she doesn't want him there

Ideally it would be best to be clear if you don't want to do shared parties (that is a perfectly reasonable line to hold, BTW). If you draw the line before the party, it will probably be easier to hold it for future parties otherwise you'll forever be battling off "Oh but the GP came to the last one".

OTOH if it's too close and he is the type to dig his heels in and try harder to cause a big scene, it might be better to try to mitigate damage by saying no to the younger DC but not objecting to the adult guests, and then next year just book it on your time and don't mention it until afterwards.

Can you tell a white lie and say you've checked with the venue and unfortunately the minimum age is 8 to put him off?

Other than this I would lean heavily on the capacity thing and say look - really sorry but the party is booked for X amount and they won't accept extras, so we can't accommodate the girls. You can celebrate DD's birthday with them on another day, did you want to swap the following weekend?

Whatever you decide, don't get involved in loads of back and forth and justifying, just set out the terms and leave it there. Use some kind of broken record statement like "No, that won't work."

Your ex is awful. He wants his own way and doesn't care what his DD wants. And the absolute cheek to blame it on you.

Turn round and message him.

You have back tracked on our agreement.
Organise and pay for your own party and then you can invite who you like."
I will drop DD to you now.

So what if he complains. Let him.

Don't start worrying in advance what DD will or won't think. The poor girl already wants to cancel. Tell her you think it would work best if she sees her dad and everyone else after she's had her party with school friends. And that' is it. She will be relieved you have made the decision for her.

You sound like such a kind mum... but now you've got to be a tiger and stand up for yourself and your DD.. Stop anticipating what your bully ex and his fam think.. Decide what you want and stick to it. Exactly like he does...
Practice trotting out "No that is not possible. " No I am not doing that." "No that is not what we arranged and I am not changing plans at this stage." "No we will stick to the plan".

You are too nice and because you've been kind and co operative, he takes advantage and thinks you are pliable and will bend if enough force is exerted. Stick to your guns.. All the words are sticks and stones.

And don't let him use that lame excuse of you are upsetting DD. He literally knows that's the trigger to pull when he wants you to cave. He's the one doing that. ..and it's just pure emotional blackmail. How the hell are you ever setting out to upset your DD, sounds like you are doing everything you can to help her. Have some stock phrases ready to squash this. The idea is don't argue. State what is going to happen. and then stick to it

Seriously... what's he going to do?

You need to make it very clear that if GF and kids turn up they will not be allowed in for health and safety reasons. Not up to you, it's the venue etc.

Though if it's going to ruin DD's birthday worrying about dad's entourage crashing the party, I would maybe go along with her plans to cancel, do something lovely with her and reschedule the party for another time. And absolutely ask him to reimburse me the money I'd lost through him being a dick.

Have you not got an arrangement where you alternate birthdays and Christmas? That is, one year she’s with you on her actual birthday, the next year with him? That helps stop the uncertainty and arguments, and means everyone knows what’s what.

With this arrangement, if it was his year to have her for her actual birthday, then that would be fine as it was his weekend anyway. If it had been his year and her actual birthday was on a day she was with you, you just swap that one day.

It’s also easier for your DD as she’d know not to ask you to organise a birthday on his day, and you could decide a different day for the party with her.

The only way he’s being unreasonable is by agreeing to it but not mentioning he wanted to come and bring others.

It must be a very tiny hall if the capacity is less than, what 20 people? In any case I can see why it would cause ructions to have your mum there but tell the other grandparents they’re not welcome. The GF and her dc I get, because they are younger and your dd should have the friends she wants there not hangers on of her dads family.

Its really unfair when the wants of adults put kids in a position like this. I wouldn’t cancel but I would compromise as much as possible just to keep the peace for your daughter. If he really won’t budge then just tell him not to bother coming at all.

Parents, maybe, but not grandparents and the rest of the hangers-on he wants to bring.

if it was just the father wanting to come then I doubt OP would have started this thread.