Party pooper - How to respond?

No, you actually have an angry, argumentative tone rather than a thoughtful one that's suitable for discussion. I see you want to be right, so you just go on and do that.

Or the other mother decided the OP brings way too much drama and just wanted to back off from her?

You're choosing to only take bits of the OP that suit you. Did you read the first post? The other mother might just be a bitch and used to doing what she wants so she might just assume OP will be fine with it? If we're going to add extra assumptions that would be mine. In fact she's probably the sort of person who will then make OP is the unreasonable one, and have sudden amnesia about all of the other details.

Cowbags daughter has told my son that she would prefer to go to his party but her mum wants her to have more female friends. The daughter is really sweet and shy.

In thinking how to react, I’d bear in mind that the objective has to be not to do anything which will jeopardise or damage this natural friendship for your son.
Not only does your son value the friendship but it seems the little girl does too and it seems clear that the awful decision was made by the mum not by the child.

Let your son know that he can still invite his friend over after school and at the weekends/holidays as usual but that if her mum is trying to encourage more girly friendships then she may not always be allowed to accept.
I’m sure you are trying not to let him see how upset you are.

As for when you next meet Cowbag in person, I would be polite and try not to make it awkward but I’d definitely not be relying on her friendship anymore as she isn’t to be trusted.
If she asks about your son or his party, I would feel free to say how glad you are that they talked it out between themselves in a really mature way, - but otherwise, be deliberately vague eg ‘yes I hope the weather lasts’ or ‘we are all looking forward to it’ and then change the subject or move away to talk to somebody else. The party is no longer her business and will be successful in spite of her ill-mannered decision so there’s really nothing else to be said on the subject so it needn’t be a topic of conversation with her any more at all.

It’s so difficult not to dwell on the hurt on behalf of your son, but put it down to an important life lesson for him and know that he will get over it quickly and begin to find his own way with friendships in time anyway.

I like the idea previously mentioned, of saving a party bag or some kind of momento from the party for him to give to her so that she knows there are no hard feelings.

You don't know my position because you're arguing with me without reading it first.

As I said, yes, I do think that in general, a child should have to stick with the invitation they already accepted. I'm surprised at the number of people who don't agree with that, in fact.

However, no, we don't know that the other mother "tried to change the activity to suit her daughter."

We don't know why the other mother decided to back off from the OP and her son's party in favor of the other invitation.

But, as you say, yes, the other mother did know the whole deal. Therefore, she must know this is gonna be a giant issue with the OP.

Therefore, rather than it just being sloppy manners about accepting invitations, I'd wager the other mother means to cut ties with the OP. I mean, all things considered, isn't this pretty much like a slap in the face?

However, we can't know for sure what's going on at the other mother's house so there are a lot of gaps here.

OPs friend knew the situation and actively planned this party with the OP, and went so far to change the activity to suit her daughter. That's poor form. I don't see any way you can try and justify that

This

I'd go nuclear OP. Shitty behaviour absolutely must be called out.

I am blessed with a grown son who is on the autism spectrum, thanks.

And if you are going to ask people to take their time to help you with your issue, etiquette requires considering them rather than lashing out when not told what you want to hear.

As I said, I think the other mother likely backed off because you're too much work, not just because her daughter got another invitation.

Setting up a party that requires eight kids minimum when you have a hard time filling those spaces, then putting the whole weight of the party happening on a friend's shoulders is a good way to lose a friend. That is not good etiquette.

As I said, I had enough to do to handle my own kid's parties. I would not want that much responsibility for someone else's too. You should expect some cancellations. Period.

Wow. Your response has absolutely nothing to do with what I actually posted. Please read before arguing.

And fyi, show courtesy yourself before preaching about it to others.

She should have.

Teaching and enforcing decent behaviour takes precedence over a couple hours enjoyment on a Saturday afternoon. It’s called parenting v pandering.

Paintball hurts like a bitch. I hope your boy has a wonderful time 🙏 😻❤️

Ugh.

Can your husband continue for a while?

Get some dark glasses and be busy/on the phone if you must be there.

Aw I’m sorry OP. That’s crap and I would want to ghost fuck out of her too. But I probably wouldn’t because of the impact on my child. It would be an incredibly hard pill to swallow.

To be honest though, she’s maybe starting to worry about her daughter not fitting in with the girls, wanting at 10 to encourage some female friendships, wanting to make sure her daughter isn’t on the outside of the girls in her class. Whilst I think she has gone about it in a horrible way (and I certainly wouldn’t have done that myself), I can sympathise with that a bit.

I'm probably not the best person to advise as I tend to just say it as it is.

So I'd just say, "We both know that you blew off DS's party for another party despite having RSVP'd, and that I'd planned the party around having 8 children. It's really rude and hurtful of you and it's shit parenting to teach your daughter she doesn't have to honour commitments she's made to her friends."

This.

What can you do? You tell your daughter that she has already committed to someone else and it would be incredibly rude and hurtful to now take back that commitment because you had a better offer. Teach your child some manners and how not to be completely selfish.

Tough shit. She’d already committed to someone else. You just don’t do that. What a terrible example to set her daughter.

And of course it’s personal. If my friend cancelled on me because they had a better offer, I’d take that fucking personally. It’s incredibly rude and bad mannered and definitely personal!

I'd suggest:
Thanks for letting me know. As you realise, this will now mean I will probably need to cancel the party. I really wish you had been clear that you were only a tentative, as I wouldn't have changed the activity to suit your DD or committed to an activity that required a minimum number. I hope DD enjoys x's party.
Definitely call her out, but don't expect anything from her as people like this don't usually feel any guilt. I hope your son has a wonderful day!

How often must you see her, and under what circumstances?

It’s a dilemma for you.

What’s that expression: “when people show you who they are, believe them.”

💐💐💐

Exactly.

They are proud of being ignorant, backward and antisocial!

No aspiration whatsoever to better themselves or their children.

Bear in mind that the daughter might seem like a good friend at the moment because her mother can control who she talks to. It's very unlikely that the mother has forced the daughter to choose the other party. People are basically suggesting her mother should have forced her to go to the one she doesn't want to go to.

Wow. This is just beyond the pale. Talk about speculation and fabrication.

And fyi, etiquette and manners don’t only apply to weddings. It’s not too much to expect decent conduct by children.