To think it's ridiculous to fall out over a Facebook post ?

You should not have used your child as a weapon, children are not there for that, you need to grow up, also it sounds very spiteful that you didn't mention them in your Facebook post either.

Maybe she is awful, but I’m not surprised she was upset by the caption to your Facebook post. It reads as if you’re deliberately writing her out.

I think OP has been raised by a manipulative person and doesn’t know how to get what she wants without resorting to the same behaviour

I agree, but the likelihood is that this goes back further and the mum was raised that way too. Each one sees themselves as the victim and the cycle goes on.

YABU to write "my little family" it's really cringeworthy. What's with the "little" trend everyone started doing?

I read about the original argument and your Mum does sound a bit self centred, needy and jealous.
The way you are handling it sounds counter-productive. You need to ignore and starve the drama not fuel it.
You know what you threatened was OTT and you didn't mean it. Don't make threats that you don't want to carry out, only consequences that you are serious about.
The Facebook post was goady.
Grey rock and walking away would be more effective.
It doesn't sound like your Mum is someone you could have a reasonable discussion with.
Your proposed child care arrangements sound risky for a lot of further arguments.
Perhaps you could let the dusk settle and then tell her that there's no need to be so negative about your in-laws-they aren't in competition and it was embarrassing in front of your husband. If she goes off on one again I would step back.

I saw lots of attack on you and wanted to give you some support. It seems to me as if you wanted to offer an olive branch but she wasn’t ready to accept it so carried it on with the argument. Having grown up in this environment, you are so used to joining back in and find it difficult not to.
A great piece of advice I’ve been given is that you don’t need to go to every argument you are invited to. Try and find a phrase to buy you some time if your dm tries to start an argument. Or a way of deflecting. Don’t try and reason with her or make her see sense or explain your side of things because that is arguing. Practise things like ‘oh I see’, ‘Right’, ‘interesting’, ‘anyway, how was the dog when you got back?’
Right now, I’d leave it a week, then phone to chat about something else as if nothing happened.

I agree with this. I think many of us model the behaviours of our parents in arguments - or go the opposite way. Maybe spend some time thinking about how you want to react next time so these types of arguments happen less and you don’t end up feeling bad afterwards.

Also - I do think your mum sounds difficult to get along with and you did try to make things better, so you did well with that.

Agreed. No one is in the right here.

Think you're getting a bit of a roasting here OP but I read your original thread and your mum did sound really unpleasant and difficult. Maybe the Facebook post was a bit goady, but I think you'd have got a bit more support here if you'd given more context about the initial argument.

Sounds like your mum can be petty and childish and you are following suit. Many people would be grateful to have parents/children still alive rather than wasting their time playing games and getting involved in drama. You both need to grow up.

Is your Mum worth having in your lives Op?

If so then you both need to find a way to communicate in a different way.

I don't see why it should be all up to Op to do.

She has learnt from her Mum.

If it was a friend how many posters would still bother themselves with the friend & the drama?

Why are parents held to lesser account?

This.

Both of you sound VU, but particularly you, threatening her not to see her own grandchild again over nothing! Awful behaviour. 😬

If she paid for the holiday then you are way out of order.

She didn't.
The OP paid.

1. Your both adults.
2. Adults have choices including how they behave
3. Your child should come first and arguing in front of children, seriously?
4. Give your child the childhood they deserve. If you are angry, walk away rather than say things you shouldn't.
5. Do what is best for your child.

I think some posters are frustrated that you won't acknowledge that the fb post was goady.

She's unlikely to change and the fact that she didn't speak to your brother for a year suggests she can hold a grudge. Think very carefully about whether you are going to use her for childcare or not.

You sound like deserve each other.

The thing is, none of us replying understand your relationship with your DM and AIBU can sometimes offer perspective, but often it can be brutal and invalidating eg this pile on about you threatening her with not seeing her DGC.

From what you say, you know that your DM is anxious, needy, insecure and emotionally immature. Resulting in her emotional blackmail and/or looking for constant validation. You two are engaging in an unhealthy dynamic. Is she worried that you won’t need her as much now you have your ’own’ family? Does she have abandonment issues?

It’s difficult to learn boundaries when you’ve not had them role modelled but you are more self aware so it’s up to you to role model the behaviour that you’d like your DD to learn. That means not rising to your DMs bait, not reacting when she mentions your DHs family. Practice shrugging your shoulders and saying ‘no, it’s not like that’, then divert and distract. As others have said, don’t let her push your buttons and don’t engage with the drama.

if you want to be the big one here, then add another photo of your parents from the holiday. Recognise that you were subconsciously punishing her by omitting any mention of them. Then move on and work on removing the reactive emotions. For hers, yours and most importantly your DDs sake.

You sound very unreasonable to ask anyone to apologise!
An apology in my opinion is something someone offers when they have been wrong and are regretful! Not something they do when asked to do so.

You should have apologised for your part- and left it at that.

If she didn't return it, silently leave her life if that's what you intend to do.

Take the break and take care of your own actions.

Let people do what they want to do so you can see what they would rather do!!

Wise up!

You both sound like children - it’s your child I feel bad for…. She has to live with this!!