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Share your dilemmas and get honest opinions from other Mumsnetters.

Ex disputing CMS and making rival Child Benefit claim in 50/50 care

425 replies

fixatedplanet · 22/03/2026 14:34

Hi all,

I’m really struggling with this and could do with some advice.

We’ve had a proper 50/50 week-on/week-off arrangement for the last 4.5 years. The boys (14 and 11) split their time equally between us week on/week off and we’ve always split the costs of shared things 50/50. He does his bit when they’re with him and I do mine. It has been working fine but....

The issue is income. I earn around £60k and he earns well over the £156k threshold. Because of that, even though it’s 50/50, I applied to CMS for child maintenance so he pays his fair share (it comes out at the maximum rate, around £800 a month which is a 50% discount as he has them 7 nights out of 14). I thought that was reasonable as his salary is much higher and he should pay more than half.

He immediately challenged it with a Mandatory Reconsideration, which was rejected because I receive the Child Benefit (he gave it up due to the high income charge and then during divorce said I could have it which only seemed fair). Now he’s put in a rival Child Benefit claim for one of the children AND lodged a tribunal appeal with the CMS. He’s basically trying to get out of paying anything through CMS and I could lose some of the child benefit now!!!

We are completely 50/50. He does everything on his time and I do everything on mine. But because he earns more, he should contribute more and CMS should sort this I would have thought, I should not have to go to a tribunal.I have started to gather evidence to try and show that I do more so it gives me a good chance at the tribunal and I guess he is doing the same now. I am going to get a barrister to help out at the tribunal to try and prove I do more but he does stuff too so not sure if that will help me.

I’m worried he might actually get the Child Benefit (even though he can’t claim it himself because of the high income charge) and that the tribunal might side with him. Does he have any chance of winning that? It just doesn’t feel fair because he earns much more than me even though we share all the care equally. He did offer to cover all of the shared costs but I have said no and decided to go down the CMS route as that will be more money than simply covering the shared costs.

Has anyone been through this? Can he really do the rival Child Benefit thing and what are his chances? I guess he has lots of evidence to show that we share care equally and have done for several years but he cannot even claim it so I would miss out! And what are the chances at tribunal? Surely they will see my side of things? He has started to pay me the £800 a month now so I have had a few months payment so far so that is good at least but I am worried I might lose it or be told to give it back.

Thanks in advance.

OP posts:
Thehop · 22/03/2026 14:38

This went very badly for a poster in a very similar situation. Somebody will likely be along to link her threads soon.

PinkFrogss · 22/03/2026 14:40

Have you posted about this before? If not another poster had pretty much exactly the same situation - have a search and you’ll probably find the advice you’re looking for

Velumental · 22/03/2026 14:41

That wouldn't have been my choice, if dad is 50/50 then he's doing his share despite warning more

YerMotherWasAHamster · 22/03/2026 14:42

I thought no child support was payable if the arrangement was 50/50.

sellingrocks · 22/03/2026 14:44

This went very very wrong for another poster and she pretty much lost custody of the children as they decided their mother was after their dads money and sided with him …..🤔

I don’t actually see why he should pay you a penny since you have true 50/50 split? You earn well enough - it’s not his fault he earns more than you…..

Tableforjoan · 22/03/2026 14:45

So another poster did this although not the same high earnings.

He did get awarded one child benefit which tbh is totally right if you are doing 50/50 the Normal is you each claim a child if you have two.

The extra spanner for you if the high high earner part so he may be expected to pay, he is fully within his rights to challenge it and he may be successful or he may not.

You’ve killed any nice co parenting though.

The other poster lost both her children in this argument as they moved into the dads and cut her off for being greedy basically.

NewYearNewMee · 22/03/2026 14:45

If it’s 50/50 shared care and he’s also paying 50/50 for things they need, why would he also pay CMS? Has he stopped paying for 50% of their needs and started just paying the CMS? Because that’s the direction I could imagine it going in.

Tableforjoan · 22/03/2026 14:45

YerMotherWasAHamster · 22/03/2026 14:42

I thought no child support was payable if the arrangement was 50/50.

If there is a huge income difference there can be.

lalalalalala2024 · 22/03/2026 14:45

Same thing happened to anotner poster and the father won the CB claim and ended up putting a CMS claim for the child he could claim.

I can’t find the post but as it’s 50/50 CB will likely pay. I don’t believe that he should have to pay CMS if it is 50/50 just because he earns more money.

Deskdog · 22/03/2026 14:48

I don’t think you should get anything OP. He’s taking half of the CB to prove to the CMS it’s truly 50/50. You forced him to do that. Oh dear.

Buscobel · 22/03/2026 14:49

On the face of it, it seems equitable. You pay when you have the children, he pays when he does. He’s earning more, but that doesn’t take away from the fact that he’s paying the expenses when the children are with him.

You said that you do everything equally, so how can you show that you do more. What’s the £800 a month?

Fedupmumofadultsons · 22/03/2026 14:49

fixatedplanet · 22/03/2026 14:34

Hi all,

I’m really struggling with this and could do with some advice.

We’ve had a proper 50/50 week-on/week-off arrangement for the last 4.5 years. The boys (14 and 11) split their time equally between us week on/week off and we’ve always split the costs of shared things 50/50. He does his bit when they’re with him and I do mine. It has been working fine but....

The issue is income. I earn around £60k and he earns well over the £156k threshold. Because of that, even though it’s 50/50, I applied to CMS for child maintenance so he pays his fair share (it comes out at the maximum rate, around £800 a month which is a 50% discount as he has them 7 nights out of 14). I thought that was reasonable as his salary is much higher and he should pay more than half.

He immediately challenged it with a Mandatory Reconsideration, which was rejected because I receive the Child Benefit (he gave it up due to the high income charge and then during divorce said I could have it which only seemed fair). Now he’s put in a rival Child Benefit claim for one of the children AND lodged a tribunal appeal with the CMS. He’s basically trying to get out of paying anything through CMS and I could lose some of the child benefit now!!!

We are completely 50/50. He does everything on his time and I do everything on mine. But because he earns more, he should contribute more and CMS should sort this I would have thought, I should not have to go to a tribunal.I have started to gather evidence to try and show that I do more so it gives me a good chance at the tribunal and I guess he is doing the same now. I am going to get a barrister to help out at the tribunal to try and prove I do more but he does stuff too so not sure if that will help me.

I’m worried he might actually get the Child Benefit (even though he can’t claim it himself because of the high income charge) and that the tribunal might side with him. Does he have any chance of winning that? It just doesn’t feel fair because he earns much more than me even though we share all the care equally. He did offer to cover all of the shared costs but I have said no and decided to go down the CMS route as that will be more money than simply covering the shared costs.

Has anyone been through this? Can he really do the rival Child Benefit thing and what are his chances? I guess he has lots of evidence to show that we share care equally and have done for several years but he cannot even claim it so I would miss out! And what are the chances at tribunal? Surely they will see my side of things? He has started to pay me the £800 a month now so I have had a few months payment so far so that is good at least but I am worried I might lose it or be told to give it back.

Thanks in advance.

Well honestly he had them 50/50 oaid his fair share you then got greedy for no reason but you saw a loophole .he bow is goung to take family allowance from you knowing he can't keep it .he us just reacting to your behavior. I would try and go back to original .50/50 split costs because you may be worse off and you then risk any decency between you if there is any

Tableforjoan · 22/03/2026 14:50

and yes if he now pays you £800 despite having them 50% I expect he will not provide a single pence over that for things during your time and could get really petty.

School trip in your week? Your problem.

Even things like not letting school shoes be purchased come to your house and such.

Minnie798 · 22/03/2026 14:51

He pays 50:50 of all costs and genuinely has the dc half the time. It sounds pretty equal so I'm not sure why you felt the need to go to cms in the first place.
Child benefit for one child each sounds perfectly reasonable given the circumstances you have described and it's very possible this is what will happen.

Blondeshavemorefun · 22/03/2026 14:53

So he offered to pay all shared costs and that’s still not good enough for you

meaning you pay nothing for your kids and he does pay it all - yet you said no as the cms is more money

you sound money grabbing

the money is to pay for joint kids. Not stuff for you

some people really don’t know when they are Lucky

i get £27.50 a month as the flat £7 a week rate as ex doesn’t work and she’s with me 100% of the time minus a few hours that I’m there as well when she sees him

by all means fight it but you will lose the cb as judges usually share half

Usernamechanging · 22/03/2026 14:53

Tableforjoan · 22/03/2026 14:45

So another poster did this although not the same high earnings.

He did get awarded one child benefit which tbh is totally right if you are doing 50/50 the Normal is you each claim a child if you have two.

The extra spanner for you if the high high earner part so he may be expected to pay, he is fully within his rights to challenge it and he may be successful or he may not.

You’ve killed any nice co parenting though.

The other poster lost both her children in this argument as they moved into the dads and cut her off for being greedy basically.

It isn’t greedy to expect parents to contribute to the upbringing of their children proportionate to income.

JustAnotherWhinger · 22/03/2026 14:57

You need to take proper legal advice.

If you have a genuine 50/50 then he will very likely be awarded one of the CB claims and no maintenance will be due through CMS.

For very high earners you go through court for maintenance arrangements as they can do things in more detail than CMS, who use blunt calculations with no nuance.

Unless he is a very very high earner maintenance is unlikely to be due, especially if he pays for everything on his time and half of shared expenses.

Tableforjoan · 22/03/2026 14:57

Usernamechanging · 22/03/2026 14:53

It isn’t greedy to expect parents to contribute to the upbringing of their children proportionate to income.

In the other case he was paying when he did not need to and doing 50/50 The boys voted with their feet.

she also kicked off that he might get one child benefit. Now he gets both and will get cms from her because she was greedy. Lying to get money you are not entitled to is greedy.

she lost her children for money. She lost a co parenting relationship for money. The ex even offered to stop it all if she would just be honest basically and she still went ahead.

That op also tried to make out that despite 50/50 she was the main resident parent. Very angry that she did do more when they were younger. Her house of cards fell from greed.

She’s now trying the his poisoned them against me rather then them being teens with ears and brains.

JustAnotherWhinger · 22/03/2026 14:58

Be very careful. The last poster in a similar situation who posted in here now has two teens who live with their father and refuse contact with her

MamaorBruh · 22/03/2026 15:00

My partner had this exact issue.
His ex earns plenty. He earns more.
She put a claim in to CMS and so he got one of the kids CB (even though he had to pay it back) and then put a rival claim in against her too.
So instead of her receiving half of everything, and the full £175 CB.
She gets about £80 CB and then about £290 from him, however she also has to pay him £200 for the child he has the CB for.
So she is actually worse off as she gets roughly the same amount but he no longer pays half of everything.

He is currently in the process of going back to CMS to get it shut down completely due to 50/50 equal shared care.
She does nothing more than he does. In fact, he did more nights than her last year due to circumstances!

Why should your ex pay you anything else? You earn a decent wage and are no longer together so as long as he is paying his way when he has them and 50% of the costs outside of that, it is no longer his responsibility to subsidise your lifestyle.

Usernamechanging · 22/03/2026 15:01

Tableforjoan · 22/03/2026 14:57

In the other case he was paying when he did not need to and doing 50/50 The boys voted with their feet.

she also kicked off that he might get one child benefit. Now he gets both and will get cms from her because she was greedy. Lying to get money you are not entitled to is greedy.

she lost her children for money. She lost a co parenting relationship for money. The ex even offered to stop it all if she would just be honest basically and she still went ahead.

That op also tried to make out that despite 50/50 she was the main resident parent. Very angry that she did do more when they were younger. Her house of cards fell from greed.

She’s now trying the his poisoned them against me rather then them being teens with ears and brains.

But it’s not the other case? It seems maintenance is due - a result of the disparity in incomes. This is fair.

If a higher earner in a together partnership demanded a 50/50 split of child related costs, there would be cries of LTB. No idea this is considered greed when a relationship breaks down,

Twasasurprise · 22/03/2026 15:01

In that other post, it wasn't truly 50/50. The father actually had them slightly more, as OP eventually conceded. It was the historic years that the OP was relying on, where she did more care, but as the children got older was no longer the case.

If it does go 1 child each, try to retain the younger child as payments will continue for longer. I think in separate households, they will both be considered the older child with the higher rate, but you'd need to research or get advice on that.

I do think it's likely you'll lose one, which is a shame, but a possible price to pay for poking the bear.

Can you and ex still agree a smaller payment as a compromise, while you continue to claim both CB and he withdraws his claim?

soupbucket · 22/03/2026 15:04

I think you sound greedy, he is paying his fair share on a 50/50 basis

Whaleandsnail6 · 22/03/2026 15:13

Your ex sounds very reasonable... he's offered to pay for all shared expences to reflect his higher income but you wanted more, and have now risked loosing out.

I morally don't think one parent should owe maintenance if it is truly 50/50, and actually since it is 50/50, maybe he should get half child benefit claim. Feels like you want him to supplement your lifestyle.

You have now likely soured relations, for what? Should have taken his original offer of paying all shared expences.

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