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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Blended families: how to best split household bills?

46 replies

user1469481379 · 16/02/2026 11:39

My partner and I are about to move in together. I have two children who live with me full time, and he has one child who stays with us around half the time.
I will be covering my own child specific costs (clothes, school trips, clubs, birthday parties etc).

We are now deciding how to split household bills such as groceries and utilities. Should we split per head (so I pay more because I have more children), or split 50/ 50 between the adults?

We both earn good incomes so we are not struggling day to day. He has not refused to pay anything, I just want to get clear in my own head what I think is fair before we agree something.

YABU: I should pay more as I have more children
YANBU: split 50 / 50 between adults

OP posts:
PrincessPears · 16/02/2026 13:16

fartotheleftside · 16/02/2026 13:09

Well, no, not necessarily. Assuming the DP is the higher earner, he'll still have more left over than the OP to spend on his child.

If DP's child gets a bedroom at the new house they also get nicer facilities, bigger reception, kitchen, garden etc, than potentially DP could afford on his own.

Leaving aside the emotional baggage/changes of living with stepfamily and looking at it purely from a materialist pov.

Edited

Impossible to tell re: living standards because OP hasn’t shared that. If he’s subsidising OP and her kids AND planning to have another, he’s far more likely to be spending less on his first child. Even the maintenance he pays would go down, if he pays via CMS.

OP’s said they’re not struggling financially… there’s a world of difference between breaking even and being a high enough earner to support four children and a partner.

EuclidianGeometryFan · 16/02/2026 13:36

PrincessPears · 16/02/2026 12:40

If and when you get married and try for a baby, you can discuss again, but I think you’d be very unreasonable to expect him to subsidise you and your kids before that happens.

A good salary doesn’t go far these days when it’s supporting four kids and a partner on maternity leave!

Agree, but he needs to know up front that any agreement reached now will be changed once they are married, and once a new baby is on the way.
Otherwise he could be misled into thinking the agreement they make now is for the duration.

I am of the opinion that if you marry, all money goes into one joint account, for all children and the household, bar a small amount of personal spending money for each adult transferred in their own current account.

He will become your DC's step-father. Has he thought about that? Is he ready to love them and pay for them as if they were his own?
Will you love and pay for his DC as if they were your own?
If not, don't move in together and don't get married - or at least not until all the DC have left home.

TheBlueKoala · 16/02/2026 13:47

xOlive · 16/02/2026 11:59

50/50.
You’re already covering your own child specific costs.

This! It's ridiculous starting to calculate pourcentages especially since

  1. You each pay for your children apart
2. You both earn well. Otherwise you could argue that the OP eats less because she's a woman and therefore should pay 0,7 and him 1,3 in groceries. Once you start going down that road there is no joy living together because such a hassle to calculate everything. @user1469481379 Ask him if he thinks 50/50 on bills and groceries is fair while each pay for their children's clubs, bdays, clothes etc.
Coconutter24 · 16/02/2026 13:48

PrincessPears · 16/02/2026 12:46

Also if you‘re getting no maintenance and you can’t easily afford groceries and electricity for your existing kids, please focus on your career instead of having another baby.

OP has said they both earn good incomes so aren’t struggling

Emsie1987 · 16/02/2026 13:56

For me it depends on living style - water is it on the meter or set bill - if it’s a set bill then 50/50 as doesn’t matter on usage. Does anyone work from home? If your home more or he is then even if you have kids he would use more. Groceries again depends do your kids have basic budgets and he wants fillet streak and lots of meat for dinner. One size option doesn’t fit all.

PrincessPears · 16/02/2026 14:02

Coconutter24 · 16/02/2026 13:48

OP has said they both earn good incomes so aren’t struggling

You should be in a better financial position than “not struggling” before choosing to have another kid when you both have kids from previous relationships.

“Not struggling” could mean reliant on benefits, could mean has no savings, could mean can’t afford holidays or a broken boiler…

Merryoldgoat · 16/02/2026 14:07

I find it hard to separate my feelings about blended families generally on threads like this but I try to start from what is best for all of the affected children.

In reality it’s rarely to move in all together and have more children. However in reality this happens all the time so you need a set up that minimises friction and resentment.

I wouldn’t move in with a man with children if I wasn’t willing to treat them equally to mine and that included finances.

I don’t want to be checking the split on bills and at restaurants etc. it’s not how I want to live.

I would probably work out a surplus we each need each month to service nonsense spending and our individual kids and all the rest goes into a joint pot to divide up savings, food, bills etc

Eg A takes home £3k has two kids
B takes home £4k has one kid.

You each need £400 for nonsense and £150 per kid so A puts £2300 in the joint and B puts in £4450

Might adjust for kid-related savings but this would underpin it.

PrincessPears · 16/02/2026 14:10

EuclidianGeometryFan · 16/02/2026 13:36

Agree, but he needs to know up front that any agreement reached now will be changed once they are married, and once a new baby is on the way.
Otherwise he could be misled into thinking the agreement they make now is for the duration.

I am of the opinion that if you marry, all money goes into one joint account, for all children and the household, bar a small amount of personal spending money for each adult transferred in their own current account.

He will become your DC's step-father. Has he thought about that? Is he ready to love them and pay for them as if they were his own?
Will you love and pay for his DC as if they were your own?
If not, don't move in together and don't get married - or at least not until all the DC have left home.

I agree with you.

OP seems to think her DP’s new salary will be at her disposal indefinitely, but there’s a real chance she could end up a single parent with three kids to two dads and no maintenance (because he may want the baby 50/50 like his older child). Second marriages are more likely to fail than succeed. Can she afford that?

DaffodilTuesday · 16/02/2026 14:15

Personally, if my costs were going to go up moving in together (ie because a bigger mortgage is needed), I would not do it because it would be my DC who lose out.
I would also be wary of selling a house only in my name and moving into one jointly owned; again, it would be my DC who lose out.

I think there are multiple risks but that is not the question you asked. In terms of splitting bills, I tend to think 50/50 if you are already paying for children’s costs. I mean, my 15 year old DS costs way more than me in food terms so I agree with the poster who said once you start trying to work out %, you have to factor in that men and women are not the same etc. If you can’t agree this with minimum hassle, don’t move in together or you will spend your whole time arguing about who pays what and wishing you kept your own place.

PrincessPears · 16/02/2026 14:30

OP is not giving many details which means it’s impossible to advise accurately.

Perhaps she’s moving into his house and he’s said she doesn’t need to contribute to the mortgage - note that rent/mortgage is not mentioned at all. Perhaps she has two teenage boys with SEN who will get their own rooms and never leave, and his younger kid will sleep on a sofa bed. In that case (he’s a deadbeat and) she’s a complete CF for thinking he should subsidise their food and groceries as well as pay everything else.

Or perhaps the DP and child will be moving from a bedsit in with OP, who owns a five bed house outright, where he’ll work from home using loads of electric, in which case he’s the CF if he wants to quibble on splitting the bills.

Generally speaking though, everyone should be paying for their own children if you’re not married. Otherwise resentment will build, sooner or later.

Shinyandnew1 · 16/02/2026 14:34

PrincessPears · 16/02/2026 14:30

OP is not giving many details which means it’s impossible to advise accurately.

Perhaps she’s moving into his house and he’s said she doesn’t need to contribute to the mortgage - note that rent/mortgage is not mentioned at all. Perhaps she has two teenage boys with SEN who will get their own rooms and never leave, and his younger kid will sleep on a sofa bed. In that case (he’s a deadbeat and) she’s a complete CF for thinking he should subsidise their food and groceries as well as pay everything else.

Or perhaps the DP and child will be moving from a bedsit in with OP, who owns a five bed house outright, where he’ll work from home using loads of electric, in which case he’s the CF if he wants to quibble on splitting the bills.

Generally speaking though, everyone should be paying for their own children if you’re not married. Otherwise resentment will build, sooner or later.

Exactly, OP is completely ignoring people asking about the mortgage/rent and bedroom situation and I think it’s impossible to answer in a useful way, without knowing that.

ForAmusedHazelQuoter · 16/02/2026 14:39

Depends on whose house it is, is there a mortgage etc?

user1469481379 · 16/02/2026 16:17

Thanks, all. We are both going to sell our own properties and buy a home together, with enough rooms for everyone to be comfortably housed.
Thankfully, I have a solid income, so I anticipate I will be able to provide for my children. I do not do luxury spending or private schools, so I feel comfortable that my day to day costs are manageable.
My idea of splitting 50 50 is exactly to remove friction and avoid any sense of keeping score, like who eats more or who used what. I would like to think in terms of us being a family.
At the same time, I do not want him to feel he is subsidising my children through general household bills like electricity or groceries.

OP posts:
BCSurvivor · 16/02/2026 16:20

I wouldn't be nitpicking down to the last pennies and pounds, but you should absolutely be paying more than 50%, given your situation.

Simonjt · 16/02/2026 16:27

We did me paying 2/3 (I had a child 100% of the time) and him 1/3, apart from things that were a set cost, so council tax for example was 50/50. He paid nothing towards my mortgage and I paid nothing towards his, we weren’t married, so I needed to make sure he had zero claim on the property until we were. After marriage we went with both incomes in one pot, rather than 50/50, but not long after that there was no step child scenario anyway.

OllyBJolly · 16/02/2026 16:30

We did 2/3. I paid two thirds of expenses (except mortgage as it was almost paid off when DH moved in). DH paid one third. He had no children and I had two. When both DCs left home we did 50/50 other than house expenses ie I fund any improvements such as new bathrooms/kitchen etc . The house is willed to my DCs.

Good list by @PrincessPears . I believe if you discuss and agree all of this before moving in then there is less room for disagreement later.

ForAmusedHazelQuoter · 16/02/2026 16:51

user1469481379 · 16/02/2026 16:17

Thanks, all. We are both going to sell our own properties and buy a home together, with enough rooms for everyone to be comfortably housed.
Thankfully, I have a solid income, so I anticipate I will be able to provide for my children. I do not do luxury spending or private schools, so I feel comfortable that my day to day costs are manageable.
My idea of splitting 50 50 is exactly to remove friction and avoid any sense of keeping score, like who eats more or who used what. I would like to think in terms of us being a family.
At the same time, I do not want him to feel he is subsidising my children through general household bills like electricity or groceries.

bills 55% you, 45% him, food 60% you, 40% him. If he says let’s just split everything 50/50 then that’s fair enough.

OnlyMabelInTheBuilding · 16/02/2026 16:51

Pay proportionally per number of kids.

Asdfgqwr · 16/02/2026 22:28

Both are reasonable, particularly if you will be living together as a family. You mention that you will be covering all child-specific costs. For the relationship to thrive, children should be welcomed, not viewed as a burden.

PrincessPears · 17/02/2026 08:42

Asdfgqwr · 16/02/2026 22:28

Both are reasonable, particularly if you will be living together as a family. You mention that you will be covering all child-specific costs. For the relationship to thrive, children should be welcomed, not viewed as a burden.

Children can be welcomed and not a burden just as well by their parents not freeloading! Children shouldn’t know about adult financial matters anyway.

EuclidianGeometryFan · 19/02/2026 08:23

I do not want him to feel he is subsidising my children through general household bills like electricity or groceries.

But he is going to be their step-father. He should be happy to pay for them.
This is a marriage not a house sharing agreement.

If you are not both all-in, 100% committed to each other's children, this is not going to work.

Will you be amending your will to say that if you die while they are children, he will be their sole parent? If not why not?

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