Help end medical misogyny. Sign our petition.

Help end medical misogyny.
Sign our petition.

Sign the petition

Please or to access all these features

AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

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

465 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:
fixatedplanet · 08/06/2026 21:44

In a twist I wasn't expecting, once my ex managed to get Child Benefit for my older son, he was then able to open a CMS case against me. CMS assessed that I should pay him child maintenance for our older son, so I was ordered to pay £260 per month.

He then continued to challenge the position regarding our younger son and argued that care was shared equally on a day-to-day basis. CMS accepted that argument and determined that no child maintenance was payable by either party for him.

The end result was that I wasn't entitled to receive any child maintenance at all, and instead I had a liability to pay maintenance for my older son.

After all of that, we've discussed it between ourselves and agreed to close the CMS case and move to a private arrangement instead.

It's certainly not where I expected things to end up when this all started. In the end I received two months of child maintenance payments from him before everything changed. I still don't know whether CMS will seek to recover those payments or whether they'll be left as they are.

Not the outcome I anticipated, I am sure a few of you will be delighted no doubt.

OP posts:
randomchap · 08/06/2026 21:49

So basically exactly what you were told would happen.

SoggyTissue · 08/06/2026 21:50

🙄 next time, listen.

Thechaseison71 · 08/06/2026 21:50

fixatedplanet · 08/06/2026 21:44

In a twist I wasn't expecting, once my ex managed to get Child Benefit for my older son, he was then able to open a CMS case against me. CMS assessed that I should pay him child maintenance for our older son, so I was ordered to pay £260 per month.

He then continued to challenge the position regarding our younger son and argued that care was shared equally on a day-to-day basis. CMS accepted that argument and determined that no child maintenance was payable by either party for him.

The end result was that I wasn't entitled to receive any child maintenance at all, and instead I had a liability to pay maintenance for my older son.

After all of that, we've discussed it between ourselves and agreed to close the CMS case and move to a private arrangement instead.

It's certainly not where I expected things to end up when this all started. In the end I received two months of child maintenance payments from him before everything changed. I still don't know whether CMS will seek to recover those payments or whether they'll be left as they are.

Not the outcome I anticipated, I am sure a few of you will be delighted no doubt.

Didn't another poster tell you thiswould happen?

BudgetBuster · 08/06/2026 21:58

Thechaseison71 · 08/06/2026 21:50

Didn't another poster tell you thiswould happen?

17 pages of posters told her 🙄

BMW58 · 08/06/2026 22:02

Blimey OP you were warned so much, but kudos to you for updating here

Laura95167 · 08/06/2026 22:03

fixatedplanet · 08/06/2026 21:44

In a twist I wasn't expecting, once my ex managed to get Child Benefit for my older son, he was then able to open a CMS case against me. CMS assessed that I should pay him child maintenance for our older son, so I was ordered to pay £260 per month.

He then continued to challenge the position regarding our younger son and argued that care was shared equally on a day-to-day basis. CMS accepted that argument and determined that no child maintenance was payable by either party for him.

The end result was that I wasn't entitled to receive any child maintenance at all, and instead I had a liability to pay maintenance for my older son.

After all of that, we've discussed it between ourselves and agreed to close the CMS case and move to a private arrangement instead.

It's certainly not where I expected things to end up when this all started. In the end I received two months of child maintenance payments from him before everything changed. I still don't know whether CMS will seek to recover those payments or whether they'll be left as they are.

Not the outcome I anticipated, I am sure a few of you will be delighted no doubt.

Not delighted. Although i did find your initial decision to go down CMS route because you believed youd get more money, grabby and entitled.

But we did say this would happen. I cant see how this was a "twist" after almost all posters advised you. It wasnt even about whether we agreed with your position (i didnt) just thats the usual consequences of this process. And I think, especially compared to @ProlongedAffair's situation, youve been very lucky to come out of this in such an amicable and affordable way.

Im glad youve managed to keep a good coparent situation. Best of luck

ImImmortalNowBabyDoll · 08/06/2026 22:05

fixatedplanet · 08/06/2026 21:44

In a twist I wasn't expecting, once my ex managed to get Child Benefit for my older son, he was then able to open a CMS case against me. CMS assessed that I should pay him child maintenance for our older son, so I was ordered to pay £260 per month.

He then continued to challenge the position regarding our younger son and argued that care was shared equally on a day-to-day basis. CMS accepted that argument and determined that no child maintenance was payable by either party for him.

The end result was that I wasn't entitled to receive any child maintenance at all, and instead I had a liability to pay maintenance for my older son.

After all of that, we've discussed it between ourselves and agreed to close the CMS case and move to a private arrangement instead.

It's certainly not where I expected things to end up when this all started. In the end I received two months of child maintenance payments from him before everything changed. I still don't know whether CMS will seek to recover those payments or whether they'll be left as they are.

Not the outcome I anticipated, I am sure a few of you will be delighted no doubt.

You were warned.

ElectricLegs · 08/06/2026 22:36

It's only money. I am glad that the parents are still getting on. That was the most important thing for the kids.

ProlongedAffair · 08/06/2026 22:40

My kids hate me so count yourself lucky.

MoFadaCromulent · 08/06/2026 22:41

You're lucky your ex is a much better person than you who cares about co-parenting and the knock effect for his kids

JustAnotherWhinger · 08/06/2026 23:02

fixatedplanet · 08/06/2026 21:44

In a twist I wasn't expecting, once my ex managed to get Child Benefit for my older son, he was then able to open a CMS case against me. CMS assessed that I should pay him child maintenance for our older son, so I was ordered to pay £260 per month.

He then continued to challenge the position regarding our younger son and argued that care was shared equally on a day-to-day basis. CMS accepted that argument and determined that no child maintenance was payable by either party for him.

The end result was that I wasn't entitled to receive any child maintenance at all, and instead I had a liability to pay maintenance for my older son.

After all of that, we've discussed it between ourselves and agreed to close the CMS case and move to a private arrangement instead.

It's certainly not where I expected things to end up when this all started. In the end I received two months of child maintenance payments from him before everything changed. I still don't know whether CMS will seek to recover those payments or whether they'll be left as they are.

Not the outcome I anticipated, I am sure a few of you will be delighted no doubt.

Hardly a twist when you’d been warned by multiple people, including a poster in a similar position, that this is exactly what would happen.

Very lucky for you that you have an ex that is more focussed on the preservation of your Co-parenting relationship than financial gain or one upmanship

good luck with it all

ImImmortalNowBabyDoll · 08/06/2026 23:23

JustAnotherWhinger · 08/06/2026 23:02

Hardly a twist when you’d been warned by multiple people, including a poster in a similar position, that this is exactly what would happen.

Very lucky for you that you have an ex that is more focussed on the preservation of your Co-parenting relationship than financial gain or one upmanship

good luck with it all

How someone can ask what's going to happen, be told what is going to happen, carry on on their current path regardless and then be shocked when it happens is totally beyond the realms of my comprehension.

JustMyView13 · 09/06/2026 06:15

ImImmortalNowBabyDoll · 08/06/2026 23:23

How someone can ask what's going to happen, be told what is going to happen, carry on on their current path regardless and then be shocked when it happens is totally beyond the realms of my comprehension.

I agree. But OP said they were using ChatGPT so this is probably a classic case of believing the output which had a bias input.

ChatGPT doesn’t replace good legal advice, and doesn’t understand the nuance that people who have actually experienced legal processes, are able to (and did) share.

Ex sounds very reasonable if they’re willing to play your (OP’s) games with the CMS, and then revert to a private arrangement after OP lost.

EmeraldShamrock000 · 09/06/2026 06:49

fixatedplanet · 08/06/2026 21:44

In a twist I wasn't expecting, once my ex managed to get Child Benefit for my older son, he was then able to open a CMS case against me. CMS assessed that I should pay him child maintenance for our older son, so I was ordered to pay £260 per month.

He then continued to challenge the position regarding our younger son and argued that care was shared equally on a day-to-day basis. CMS accepted that argument and determined that no child maintenance was payable by either party for him.

The end result was that I wasn't entitled to receive any child maintenance at all, and instead I had a liability to pay maintenance for my older son.

After all of that, we've discussed it between ourselves and agreed to close the CMS case and move to a private arrangement instead.

It's certainly not where I expected things to end up when this all started. In the end I received two months of child maintenance payments from him before everything changed. I still don't know whether CMS will seek to recover those payments or whether they'll be left as they are.

Not the outcome I anticipated, I am sure a few of you will be delighted no doubt.

That sucks. It’s a pity you didn’t ask for advice before bringing this forward. There is no maintenance required in a 50/50 co-parent relationship.
Can you take on an extra job in the evenings to bulk your income.

hahahaaa · 09/06/2026 07:22

Look for a better paid job if you want a better lifestyle. Or do uber eats driving in the evening

Twasasurprise · 09/06/2026 07:24

Unfortunately this was easy to predict, as we all tried to advise you. It is good for your children that you and your ex came to an agreement together.

You obviously don't have to, but as a lesson that others may learn from, can you summarise how different the financial position is for you now?

BMW58 · 09/06/2026 07:24

ProlongedAffair · 08/06/2026 22:40

My kids hate me so count yourself lucky.

I hope time heals the rift.

LiquoriceAllsorts2 · 09/06/2026 07:26

Your being very cheeky, he has them 50% of the time and pays 50% of the costs, why do you need more off him

LiquoriceAllsorts2 · 09/06/2026 07:29

of all your scenarios the answer is - you get both child benefit and nothing additional from him. You took 70% of the assets so you already have more than half, surely his extra salary needs to go towards making that up

LiquoriceAllsorts2 · 09/06/2026 07:31

fixatedplanet · 08/06/2026 21:44

In a twist I wasn't expecting, once my ex managed to get Child Benefit for my older son, he was then able to open a CMS case against me. CMS assessed that I should pay him child maintenance for our older son, so I was ordered to pay £260 per month.

He then continued to challenge the position regarding our younger son and argued that care was shared equally on a day-to-day basis. CMS accepted that argument and determined that no child maintenance was payable by either party for him.

The end result was that I wasn't entitled to receive any child maintenance at all, and instead I had a liability to pay maintenance for my older son.

After all of that, we've discussed it between ourselves and agreed to close the CMS case and move to a private arrangement instead.

It's certainly not where I expected things to end up when this all started. In the end I received two months of child maintenance payments from him before everything changed. I still don't know whether CMS will seek to recover those payments or whether they'll be left as they are.

Not the outcome I anticipated, I am sure a few of you will be delighted no doubt.

how did you not expect it when hundreds of posts on here warned you, serves you right for being so greedy

TheGreatDownandOut · 09/06/2026 07:36

I mean fair play for updating us, many posters wouldn’t in this kind of scenario. I can’t fathom why you’d have put your co parenting relationship at risk like this. I’d have had sympathy for you if your salary was much lower than it is or if your exDH was providing sub standard care or something but I can’t understand why you’d think you’d need an extra £800 a month?! In your situation, I’d be asking (not telling, maybe just suggesting) that your exDH puts some money aside for your boys each month for them to access when they’re old enough rather than giving it to you. What kind of extras do you need that cost £800 a month?!

Misnofitness · 09/06/2026 11:13

A great lesson that ChatGPT is fallible and to listen to others experiences of going through the exact same scenario.
@ProlongedAffair has been through hell but came back on here to try and stop someone having the same experience and was completely ignored

GertrudePerkinsPaperyThing · 09/06/2026 11:17

Respect to you for updating.

I hope you do listen to answers next time you ask for advice as this was all predictable.

Good luck for the future.

ThisOldThang · 09/06/2026 17:15

I don't understand why CMS was due for the eldest son, but no CMS was due for the younger son. Why weren't both children/cases found to be either CMS due or no CMS due?

Swipe left for the next trending thread