To issue ultimatum to DH about his ex?

Your H is absolutely pathetic. You must refuse to have the children on your own. He should too if there is no notice. A few missed shifts will teach her.
She is being ridiculous.

DH wants an easy life and is terrified she'll stop him seeing the children if he complains too much

who would look after the children whilst she works shifts then?

This basically.

Put it in black and white, in a text or whatsapp or something.

"I dont want you to reply to this. I am sending it while you are at home with time to think.

The situation with X has to change. You and I both know that she will not stop you seeing the kids as otherwise she wont be able to work. The simple fact is that you wont say no to her as it is easier than standing up to her.
I am now at the point where either she sends to rotas when they are released so we can plan. If she doesnt then I will not stand in for school runs, appointments, hobby pick ups etc. That is ALL on you from next Monday.
Please be aware that I am seriously considering ending our marriage over this. The fact that you would rather deeply upset and inconvenience your own wife rather than stand up to her has made me see you in a very different light to man I thought you were. . It makes me think that your ex is more important to you than I am, I am sure you can understand how heartbreaking that is for me.
Please think very carefully about this and we will talk when I get home.
I do love you and all the kids and I dont want to have end everything, but if you refuse to engage then I afraid you will leave me with little choice"

Then you have laid your thoughts and feelings out in a calm and measured way that he has time to digest and consider rather than it descending immediately into a row that will solve nothing.

She’s being an absolute dick. Rolling shifts are a nightmare with kids, so unsettling for everyone, hard to do extracurriculars and to sort childcare, and that’s even with the 4-6 weeks notice that you tend to get with a rota. She can’t do this, shes fucking you all over including the kids. Can she request set days? As a single parent she has good reason to get it approved. Your DH needs to get really firm here.

YANBU.

I am so selfish I would rather be alone than have stepchildren. It is almost always an issue.

Needs to go to court for full custody with birth mother having set contact. This is in the best interests of the children.
Would consider this abuse of the children because of the uncertainty she is creating for them.

He needs to say to send the rota at the start of each month or end of each month. Basically whenever she gets it

I'm telling you now she is NOT going to stop him or you seeing the kids because she NEEDS YOU BOTH otherwise she's not going to be able to work or will work and use all her pay for Nannie's/childminders

@PicassoDiBablo
He just needs to get a court order about shared custody. Last minute babysitting will not happen anymore. Make him tell her just that. I can't believe anyone would be so inconsiderate.

Stop running around after the children. Stop picking them up, stop cooking the meals, stop buying the food. Concentrate on your own child and yourself and let the SDCs parents concentrate on their children. You can bet your last penny DH will get things sorted if you aren't there to facilitate it anymore. They are both laughing at you, don't put up with "mug" as your middle name anymore.

The op does as well. She clearly states this, granted not in the initial op.

Yes it’s ultimatum time OP.
You can’t live like this, nor can your child and nor can those poor step children.
She will be getting her shift patterns at least three weeks in advance (my sister is hospital nurse) and there is absolutely no good reason why she can’t share her rota as soon as she gets it.
I would be saying that either she starts producing rotas and doing a bit of forward planning or you’ll be leaving him. I’m sorry but it’s the only option open to you now. Be prepared to carry it through though.

Your dh is being silly - of course she’d rather free childcare than having to pay for childcare.

The only way round this is for him to be the one who has to rush to last minute pickups and the supermarket for extra food ingredients. You make his life so much easier that he can’t have a reasonable conversation with the ex-wife. He and his ex need to be inconvenienced before they realise that there’s an easy fix.

It’s ex wife that works in NHS not op

She's not going to stop contact, she'd be left with the children all the time.

So what does he say when you point that out to him? I know it's really difficult where DSC are concerned but I think I would tell him the situation is too much for you, your child and his children. It's affecting everyone and you have had enough of it. Make him realise that he stands to loose you if he carries on being so pathetic with his ex.
She's not going to stop him seeing the kids (he has them 50% of the time and is her only source of childcare) so what's his real reason for refusing to put you and his children first!

Just don't get involved. They knew they had kids when they had them

Let H deal with the kids. Let him do the pick ups, drop offs, meals, uniform washing , homework ect. You make plans for yourself and your DC and don't drip them to be the the adhoc childcare. They are his kids and his responsibility. Let the last minute nonsense be him problem to solve. The more you pick up the slack the less motivated he will be to do something about it.

I don't think your unreasonable wanting to give him an ultimatum. I wouldn't want to live like that. However, I'm ts probably best to get your ducks in a row so you can follow through.

OP does say she works in the NHS though…

Why don’t you always just prepare for the extra child to be there, then she can just fit in whenever she gets there, should be her home too.

Yeah, I agree. Why would he mind having them extra, they're his babies too.

And so what if they just 'turn up' it's their home. The only thing I would say is if it is last minute/ad hoc, she has to drop them off or cancel the clubs. Not on you to run around unless you don't mind. Which you do. So your partner needs to do it. Problem solved. You're stressing over something that isn't such a big deal, just hand the responsibility rains back to them to sort the pick up/drop offs.

Also, how many shifts does she do? Likely step children only with you 3 max 4 nights 1x a month if she is full time.

Sounds like a power play. DH needs to get on top of this. It’s awful for everyone.

Exactly. This is not a good enough reason to not share her rota, which makes any proper planning impossible.

DH needs to stand up for everyone else in the family and call her bluff

You can issue your ultimatum of course - they are not your kids, you don't have to do anything for them really - and he can also turn around and say he's (for whatever reason) not wanting to confront her - so you then leave him. I dont think, or it doesn't sound like the ex has much recourse to childcare so im not sure why he would think there was a chance of that happening, but he does sound spineless for whatever reason, so you can either choose to stay and he doesn't change - or you leave. These poor children are the ones i feel sorry for the most. Just make sure youre prepared to follow through with said ultimatum. My SIL issued my brother one, never followed through.

Why don’t you go to court and get an order made?