To have called time on my marriage. A family of two halves.

So entitled.

Your MIL has two granddaughters - your husband's child from his first marriage, and the daughter you have had together. She is funding a hobby for her two granddaughters and you are having a strop because she won't do the same for her step-granddaughter?

As others have said if you want to make things equal then you refuse the funding. Your older daughter does have paternal grandparents, the fact they're not interested is not down to your MIL to "fix". They are kind and polite which is as it should be, anything else is a bonus and you cannot demand that they buy into your fairytale of happy blended families.

Parents who have children with multiple partners are opening their kids up to this sort of thing, it;s unavoidable. And now you're splitting up with your DH and making the children's life even more complex? Go you.

It’s horse riding - isn’t it?

The girls that did horse riding in my city had a reputation.

My cousins did horse riding and were gifted horses of their own - they were either very spoilt or antisocial.

Do hope some of these posters jump on the threads where a wife refuses to treat her step children fairly. I doubt it.

Oh absolutely. Women are not expected to take their time or resources away from their children for a step child but it's a whole different expectation on here for men and their families.

PS you didn't say what your mother has to do with it all but why is her opinion relevant?

Completely agree @Hallamule
If it was the OP's parents, there would be lots of support for them favouring their biological grandchildren.

Your husband is a shit stepdad. And you are failing your dd while you let him get away with it, sorry.

Not having been in your position I don't know if you could have forseen this before you married, but just saying "his hands are tied" and you going along with it are both pathetic. As pps have said, it's both your jobs to make things fair between your girls. You are both harmfully passive about all this.

It's an inherently unsolvable situation.

Your husband cannot really be expected to turn down opportunities for his daughter simply because you cannot afford to offer them to your daughter. But your daughter cannot be expected to be the poor relation in her own home and watch her half and step sisters enjoy lavish hobbies that you cannot offer her.

I can see how splitting up would be the fairest way to tackle it so that your shared child can partake in the activities when she is with him, and your own two children can have the same lifestyles when they are with you.

It's a shitty situation to be sure, and presumably there will be even less money in the pot for hobbies once you're maintaining two homes.

He will have to pay you child support and you won’t have to expose your eldest to unfair treatment.

Him walking out is showing his immaturity.

What about the current thread with the husband asking if his biological son might live with them full time. Wife says a resounding no. Or the numerous other threads where the wife asks if it is ok for her parents to treat her children by her husband differently to his children by his first marriage. A resounding agreement yes of course from other posters.
There seems to be a huge difference in attitude when the wife's own children are involved. Even if they are not biologically related to the in laws.

How would that help? Then you'd get the younger child resenting her older sister instead of the other way around.

I bet if it was the OPs parents paying for something and her stepdaughter missing out then no one would be seeing a problem.

So what do you want to happen in respect of the 3 girls?

Your MIL refusing to pay for step grandchild is awful, you either pay for all or none at all!
Your H is fed up of his mum causing division and rejecting a child that is part of the package he took on when he married you? Or is he fed up of his mum deliberately stirring shit in his Marriage by not accepting his step daughter as family?
If he is not telling his mum that he has three daughters who need to be treated equally or none at all then good riddance!

Your husband has a daughter from a previous relationship, you have a daughter from a previous relationship and a joint daughter. Your in-laws are paying for extra activities for your step-daughter and your youngest daughter but not your eldest daughter. In an ideal world your in-laws would treat your eldest daughter in the same way as their biological granddaughters. Unfortunately, they aren't obliged to do so, and clearly don't want too.

Can you afford to pay for extra activities for your eldest daughter, so she can join in? Would your husband help you financially, to include your daughter, if you can't afford it? It's not your daughter's fault she has no contact with her Dad or his family, but equally it's not your in-laws fault either; it's simply shitty circumstances.

If it's impossible for your eldest to be given the same opportunities as your younger daughter, because finances won't stretch, then your husband stops his Mum from funding your step-daughter and youngest. Your MIL isn't your step-daughter/younger daughter's parents... it's not her choice or decision to make.

What does your husband think should happen? I'm assuming that he's perfectly happy for his Mum to pay for extra activities and leave your daughter out????

I'm sure the OPs frustration here is geared towards her husband, who she is now divorcing. He could have handled this better, but I guess he wants his daughter to enjoy his family's money too.

That's fine. Divorce seems reasonable in that case.

I think this is the reality of many blended families.

It’s not up to your IL’s to ‘even things up’ for your daughter who is not their granddaughter. That’s yours and your DH’s job.

Anyway it sounds like your DH has taken the decision out of your hands anyway.

It could be better this way, at least your youngest won’t have to miss out on the things her grandparents want to give her, but it won’t be so much in your eldest child’s face as she’ll be doing all that stuff in her 50% time with her dad.

And neither do I understand the divorce thing? 😕

Am I correct that MIL doesn't pay for something that your oldest daughter we would like to attend, they are not related and oldest daughter can't understand and is upset? The answer is that you pay and explain that MIL is not her grandmother?

I’m sorry OP but I don’t see how divorce will change things? MIL will still continue to fund DSD who doesn’t live with you and DD3 who does so your DD will still feel excluded, possibly even more so 🙁

What is splitting up going to gain?
Ex MIL is still going to be paying for hobby, SD and younger daughter will still be doing hobby (50:50 custody, he will have a say in her hobbies). You will still be in a situation where one child has an involved father and paternal family and all the benefits that this entails and another daughter that doesn’t, plus you lose time with your younger daughter who now has to deal with living between two households.

I’m not saying it’s fair or right, but I am saying that surely there’s another way as splitting up isn’t going to magically fix these things.

I'm guessing her husband is too much of a wet weekend to put his foot down and make that call to say no to the funding for the hobby hence "his hands are tied".
While there's no obligation on the MIL, that's a horrible way to treat a child, both of them in fact as they'll grow up with a lot of resentment poisoning their relationship and that of their parents. Which anyone with some self awareness would know.

So Granny is paying for your youngest and her step sister to do pony club and your older daughter would also like to do pony club and you can't afford it so she feels left out? In that case your either pay for oldest to also join in or neither of your two does pony club surely? You can't decide what is done for step kid.

Exactly this.

MIL doesn’t get to dictate what happens.

But why do YOU allow your youngest to attend given you can't afford for yiur other daughter to attend?

You are their parent... you get to decide.
You need to stand up and say "Thanks for the offer but we need to let it pass as we can't afford the same form Daughter 1"