To have asked for plans to be changed slightly.

So... have the kids actually said they want their mum and dad back together? And has their dad explained that actually their parent's separation is nothing to do with "breakdown2025", and that even if she wasn't in the picture, they wouldn't get back together?

Did one of your children do something to them? For things to change so drastically where they won’t even come to your home is an enormous red flag.

I think in your husband's shoes I'd be walking away from the marriage. Presumably there are financial reasons he doesn't, as you're the higher earner. Who's paying for this hotel?

Do you think this relationship (the reality of it) is helping your MH or impairing it?

It’s not really changing plans though, it’s reducing contact with his children

What are your own kid's feelings on it all OP, you haven't said much about them?

Are they happy you got married?

How do they react when their much younger step siblings wind them up?

WHY was it so bad that your SC had to stay in a hotel rather than at your house?

What was 'unsustainable' about a bit of step sibling rivalry that this extreme and expensive measure had to be taken?

Honestly, cut your losses.

It isn't "special". You're unhappy to the point that you have previously felt suicidal. He is absent for half of the week. Your kids can't even be in the same space together.

This is not a happy way to live. You have no shared property, no shared children and no financial dependency. Just walk away... you will probably feel an immense sense of relief.

Given the age of your kids, can they stay home while you go out with husband and his kids for lunch? I'm not only thinking of reintegration plans, but most importantly, just trying to get you through this weekend while you're struggling, by not having you alone for long periods.

It doesn’t sound special at all. It sounds substandard to an average marriage

I was a step child from the age of 9 and the thought of my dad leaving the home with stepmum for a whole weekend with us - well there's just no way it ever would've happened!

I'm sorry to hear that.

This dad is at least doing all he can to see his children while they're not allowed to stay at his house.

And I'm still not sure the OP has told us the full extent of why he's taken this rather extreme measure.

You say your DSC see you as the obstacle to their parents getting together again, and that someone made trouble by showing them photos of their parents' wedding. But I’m not convinced that either of those things is the case. I think showing them the photos was a perfectly natural thing to do, and surely your DH could easily explain to them that he and their mother split up long before he met you (assuming that’s true) and that there is no prospect whatsoever of the two of them getting back together.

I hope things improve for you soon, but asking your DH to spend less time with his young children so he can spend more time with you would give them further cause to resent you.

So split?

You either don't want his kids in your house and/or you made them feel so unwelcome that they don't want to be there.

Your H has responsibilities as their father, so he stays away every weekend in order to fulfil those responsibilities.

So he is going to be a part time husband, inevitably?

It doesn't sound like there is any realistic prospect of you playing happy families any time soon, so you either decide to live with the status quo or you decide to leave.

It isn't reasonable to start demanding that your H spends less time with his dc in order to support your mental health. You are an adult and they are dependant children. Their needs have to come first.

It all sounds pretty tough, OP. Ultimately, if the family set-up isn't working (and it sounds like you've all been trying for a while?), then maybe you need to consider splitting up.

I'm not someone who thinks blended families are bad and you shouldn't move in together if you have kids, I think there are so many different situations. It works for some, and doesn't work for others. In your case, it doesn't seem to have worked.

You do have a part-time husband due to his ineffective parenting and not being able to handle two small kids, winding up their older step-siblings.

If every parent in his position made the kids stay in hotels rather than deal with it, there's be a massive boom in the leisure industry.

I'm going against the grain here - yanbu.
It's unsustainable for him to spend these weekends in a hotel - completely ridiculous actually. I'm all for dads seeing their dc, but this is too much.
I was a step child from the age of 9 and the thought of my dad leaving the home with stepmum for a whole weekend with us - well there's just no way it ever would've happened!
Good luck OP - and I hope you feel better soon.

Okay I understand you. If you think divorce through with the practicalities of housing etc do you feel life would be better?

Yes but the OP already has their father's company more than his children do.

It’s confusing what you think you want tbh. On one hand you feel you need him at home to help you with your mental health and with your children. On the other you’re considering divorce which means he wouldn’t be around to do either and you’d be on your own with your ex the only option to help with your kids and you say your ex can’t have them more than he does at the moment.

What's happening about the behaviour of relatives who have apparently caused all this?

I think it's too easy to blame them and DH's DC.

You seem fully confident that the tension in the home is 100% from his children. Are you honestly, genuinely able to say that your children are completely the victims and there is no 50/50? No winding up of the SC by your DC?