It's a MIL one - stop me before I say something I'll regret

If sil didn't know perhaps you should tell her now but I fail to see how your mil wouldn't have let her know the plans. I still feel its up to sil to reassure her mother she's fine with her going on the break for the duration OP & indeed encourage her to do so

She’s saying that she’s still going to come and just go to the nativity

So are you going to say “no” to that?

My DD is not the favourite, she is the first GC but my MIL doted on my BIL’s DD once she came along. Kids can be really astute about this sort of thing and my DD started to gave MIL the cold shoulder when she was about 4. In the end after being asked several times by MIL why DD wasn’t friendly to her, I had to explain it was due to the favouritism. My MIL did change her behaviour but their relationship has never really recovered. I feel sad for them both.

Your MIL is being incredibly rude and thoughtless. You have every right to be hurt, you’ve put time, money and effort into a lovely holiday and they are ditching you. Like others have said, downgrade the relationship after the holiday.

All the people on here who are trying to excuse the MIL awful behaviour.
If I book to go away with one of my friends,I don't ditch them when something else comes up.

She doesn't have to do it. She could explain that she has had this trip booked for 6 months and she has sat down with her son and his wife and agreed activities so she can spend time with her other grandchild.
No one is forcing her to go to the nativity.

In her defence she wouldn't have known when the Nativity was

And maybe her grandson would have been upset and she's stuck in the middle

Just as much the fault of OP sil

She’s doing both as she’s going on a Christmas trip with one DGC while also going to the nativity or the other. Hence the 3 hours of driving which I’m sure no GP would particularly want to do.

100% this.

It is ridiculous to drive back and forth like that on 3 successive days.

But what can you do?

I would have DH tell her that you are both sad that she will miss DD’s first Santa visit as that is something you had hoped to share with them. Don’t frame it as annoyed, just sad. And DH has to say it’s both of you.

Unfortunately you have been performing the ‘pick me’ dance which tends to end in disappointment.

Sorry OP. Actions speak louder than words. I would tell them not to come.

That's appalling. You have every right to feel hurt. It is pointless them joining you at all. They are not even planing to rush back after the nativity.

If they do join you and then leave, missing the main day, it will ruin the day (and potentially the trip) for you as, with the best will in the world, it will annoy and upset you that they are leaving and missing all the special activities you have booked.

I think you should suggest they don't come at all. Take friends / family that do want to spend time with you or go alone as a family .

My granny vastly favours my cousin. I don’t think of it in terms of she “likes her more” , they just have a closer relationship, partly circumstance, partly lots of different things. I know she loves me and I love her. It really doesn’t bother me that much. I know it used to irritate my mum a bit, but honestly competing with others over who’s closer to who never did anyone any good in any context.

I think your MIL seems to be the domineering presence and your FIL and DH probably just goes along with it. When people like you OP (from the ‘outside’) come into this and know what a healthy dynamic looks like, it can be a surprise to those in the trenches, as it is just ‘how it has always been’ (MIL making all decisions and FIL and DH following the same old pattern for years).

It won’t change. I agree with PPs that suggest to cancel the in-laws invite. Maybe can some other family or friends take the booking?

My MIL is the same. She favours her DD’s kid. She doesn’t bother connecting with us at all. Our DC is a toddler and does not know her. Similar to you OP, I extended myself many times only to be pushed back. The latest visit she complained she was missing a get together of some social group that she sees regularly versus seeing her grandkid, her DS and me. It was three months between visits. I apologised to her for missing out her group get-together and stopped initiating anything on my end. DH communicates with her, I don’t bother anymore, no cute messages about her grandchildd, no calls, no more care packages - she doesn’t do anything back why should I waste one more moment of time.

I’m fortunate DC has interested grandparents on my side.

Reading this makes me so grateful my son & dil ensure both sets of Grandparents see & interact with their Grandchildren equally including alternating Christmas days.

In your shoes, I would be saying "I think it's best that we do a joint trip another time when you are not double booked, as it's going to be confusing and upsetting for DD if you have to leave part way through." If she comes back with further nonsense about the grandfather driving back and forth, just say that you've already cancelled their spots.

I hate it when people double book and pull shit like this and I always cancel if they suggest a half-arsed version of what had originally been planned.

If you go along with this, you're giving her the green light to always see plans with your DD as flexible and pull similar stunts in the future.

I think you definitely need to address it with your in-laws. Or else these kind of things will keep happening and it'll turn into something bigger.

I speak from experience after years of my in-laws favouring sil dc. My dc didn't get a look in. And because my DH didn't want to confront them about it, well they just carried on excluding our dc. Now they are adults and they hardly see their grandparents. They have no close relationship, it's a four times a year quick visit during which time mil bangs on about the favourites almost the whole time.

And it has affected our dc. My own parents have passed and I don't have much family my side. They really needed and wanted all the good times with grandparents. It's totally ruined any relationship between the cousins. It's caused a fracture in the family. They tell me they are angry and don't want to really see them now and that they have been made to feel not good enough.

My eldest graduated from uni last year. We were allowed four tickets. We asked mil to come and she was thrilled. We booked a lovely meal for afterwards. Two days before graduation she told us she couldn't come because sil was going away for the weekend and she needed to mind her dog. Final nail in the coffin for my dd.

I feel for you, it's horrible behaviour on their part. I'd bring someone else along with you as you'll be uptight with them there. Can your DH not speak out and say how hurt he is?

A grandchild’s nativity play, when he was in one last year and he’s only 3.5 absolutely doesn’t seem like a big thing to miss. My parents didn’t come to any of my children’s ones. Plus tickets were generally max 2 per family.

No don't do that. That will set the scene for everything going forward. Why should op change a date that has been discussed, booked, paid for to accommodate a bloody nativity play.

@TheFairyCaravan

I see far more of my own mother than her daughter in law, and my children therefore do too.

Mum has a very natural relationship with me, but is more uncomfortable around my DP - or any of my siblings partners.

Rightly or wrongly, I think it’s the grandmum/the daughter that tend to be involved more in social situations etc.

That bond is typically going to be closer with the GM and her own daughter - plus the dynamics associated with this.

That said, I don’t think any grand children are loved less, it’s more about the social dynamics that play out between a GM and her daughter v’s daughter in law.

Can you not move the holiday dates OP?

That's what I'd do too.