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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

To think "half your age plus seven" is a massive pile of nonsense?

370 replies

TransportNerd · 01/07/2026 08:07

Mumsnet seems to take a very dim view of age gap relationships, far more so than I think the general population does. I've seen plenty of age gap relationships work just fine.

Every single time they're discussed here, though, someone wheels out the "rule" that you shouldn't date someone younger than half your age plus seven years.

People treat it like it's absolutely set in stone, and that breaking this "rule" is some sort of disgusting taboo. I've even seen someone argue it should be enshrined in law, with penalties for those who break it.

Personally, I've always thought it was complete nonsense. It was simply something in a French novel in the early 1900s. It doesn't really take anything important into account, and ignores the principle that consenting adults can do what they like.

Quite apart from anything else, why is it plus seven? Why not five, eight or ten? I'm sure it's only seven because that's a number that's had mystic significance since ancient times. Not a good basis for making laws!

Anyway:

YABU - yes, it's a rule and shouldn't be broken
YANBU - it's a big pile of nonsense and doesn't mean anything

OP posts:
MumsTheWordYouKnow · 02/07/2026 19:17

shuggles · 02/07/2026 19:03

What on earth is a "power imbalance"? Does one partner use more electricity than the other partner? Seems like a very strange word to use within the context of interpersonal relationships.

Have you been living under a rock? Maybe look it up on Google

MumsTheWordYouKnow · 02/07/2026 19:14

likelysuspect · 02/07/2026 19:10

Absolute rubbish

Posters on this forum are obsessed with supposed power imbalances and love to throw around the word vulnerable.

I was in a 15 yr age gap relationship so I know what I’m talking about. Assumptions!

envbeckyc · 02/07/2026 19:12

TransportNerd · 01/07/2026 08:07

Mumsnet seems to take a very dim view of age gap relationships, far more so than I think the general population does. I've seen plenty of age gap relationships work just fine.

Every single time they're discussed here, though, someone wheels out the "rule" that you shouldn't date someone younger than half your age plus seven years.

People treat it like it's absolutely set in stone, and that breaking this "rule" is some sort of disgusting taboo. I've even seen someone argue it should be enshrined in law, with penalties for those who break it.

Personally, I've always thought it was complete nonsense. It was simply something in a French novel in the early 1900s. It doesn't really take anything important into account, and ignores the principle that consenting adults can do what they like.

Quite apart from anything else, why is it plus seven? Why not five, eight or ten? I'm sure it's only seven because that's a number that's had mystic significance since ancient times. Not a good basis for making laws!

Anyway:

YABU - yes, it's a rule and shouldn't be broken
YANBU - it's a big pile of nonsense and doesn't mean anything

My husband and I started dating at 17, so using this logic I would have been calculated to 15.5 years old - one of us is two months older than the other!

To be fair.. that was over 30 years ago… this calculation is bollocks!

likelysuspect · 02/07/2026 19:10

MumsTheWordYouKnow · 02/07/2026 18:30

Personally any gap of adults beyond 7 years is serious ick to me, power imbalance.

Absolute rubbish

Posters on this forum are obsessed with supposed power imbalances and love to throw around the word vulnerable.

likelysuspect · 02/07/2026 19:05

Ive not heard one person in real life talk about this, or refer to it or think its some sort of real thing

On here however people actually refer to it like is actual law or social norm or wisdom that they're imparting to the thread, they gather themselves up as a font of knowledge and then spout this nonsense

They sound like twits.

Phonicshaskilledmeoff · 02/07/2026 19:03

I mean - it certainly isn’t out of kilter with what feels about right though. Aged 25 - 19. Aged 35 - 22,m, 45- 29…etc

It’s not how I’d judge my life or relationships, but I certainly wouldn’t find myself straying outside of that rule (not because of the rule but because it’s not wrong!)

shuggles · 02/07/2026 19:03

MumsTheWordYouKnow · 02/07/2026 18:30

Personally any gap of adults beyond 7 years is serious ick to me, power imbalance.

What on earth is a "power imbalance"? Does one partner use more electricity than the other partner? Seems like a very strange word to use within the context of interpersonal relationships.

TeamGeriatric · 02/07/2026 18:55

I think we need some details on how we are supposed to vote on this, I am not sure I voted correctly. YABU means the rule is fine, but does YANBU mean that we think a more extreme gap is fine? I think a 60 year old dating a 37 year old is odd and a bigger age gap is even weirder, so I voted YABU.

BillieWiper · 02/07/2026 18:53

Well yeah it's just made up nonsense isn't it. You could just easily say any other set of numbers or sums.

Human adults can and should date whoever they please if all consent. If someone is an abusive wrong 'un then they're bad news regardless of who they target.

I mean I don't think teens should date octogenarians but essentially it isn't really my business if it's legal.

Where other people who are strangers wish to place their tongue or genitalia isn't really my concern. If they are consenting.

ImImmortalNowBabyDoll · 02/07/2026 18:53

I think it's a good rule, and honestly it should be an absolute maximum in terms of an age gap.

Obviously no-one is bound by it but it tends to make sense. Occasionally, you get a big gap that works out well, but rarely. A 30 yo going out with someone under 22 is weird and predatory. There's a power imbalance there, even if you don't think there is.

A 40 yo can date someone under 27, but why? Someone in their 40s SHOULD be leading a different life and have different priorities than someone in their early to mid twenties.

A 35 yo going out with a 60 yo is going to find that options like having children, home ownership and any life that doesn't involve becoming their spouse's carer are closed or very limited.

I met my husband when I was 26 and he was 34, that's an age gap but it means we both fall into the same demographic, get the same references, and wanted the same things on a similar timescale, i.e. marriage, kids, mortgage.

GeneBelcher · 02/07/2026 18:53

OK the rule itself seems a bit daft but there is always something off with the older person in an age gap couple.

IcedPurple · 02/07/2026 18:52

OnionB · 01/07/2026 09:20

The earliest reference was Patchwork by Frederick Locker-Lampson in 1879. It was considered an ideal, not a minimum.

And the assumption, of course, is that the woman would be the younger partner.

I doubt the idea of a woman dating a considerably younger man even crossed the author's mind.

Frugalgal · 02/07/2026 18:46

MumsTheWordYouKnow · 02/07/2026 18:30

Personally any gap of adults beyond 7 years is serious ick to me, power imbalance.

Nonsense.

FreightNot · 02/07/2026 18:42

Like most topics on the internet, people want rules that they can broadly apply to vast swaths of people. The reality is much more nuanced and individual. Tricky for some to understand.

MyGrains · 02/07/2026 18:42

BuildbyNumbere · 02/07/2026 18:33

How dramatic

Fortunately for you, my thoughts won’t affect anyone entering one of these creepy relationships.

BuildbyNumbere · 02/07/2026 18:33

MyGrains · 01/07/2026 09:04

Yep. Hating age gap relationships is one hill I will die on. When I hear about a very young woman being with a man in his 30s or 40s I feel a bit ill. And then the woman often says well I was a very mature 19y and he wasn’t. Who wants to go out with an immature 35 year-old?!. Luckily my kids are young adults and have no interest at all in much older partners.

How dramatic

coocoocachoop · 02/07/2026 18:31

Literally never heard of that rule ever and I’ve been on a lot of these threads, tbh it’s far more lenient than what I’d accept as a reasonable age gap. I think people forget how challenging age gaps are as you get to 60+

Biggles27 · 02/07/2026 18:31

10 year age gap here with dh being younger. We didn’t meet the half + 7 rule when we got together

Been together 31 years, married 27

apparently we’re one of the happiest couples our friends know! Two further couple friends of ours have the same age gap and been together a long time. One married 20 years last month, been together I think 35 and the other one has a 23 year old and married 19 years All very happy

BuildbyNumbere · 02/07/2026 18:31

Never even heard of this supposed rule. Who cares what MN says anyway.

MumsTheWordYouKnow · 02/07/2026 18:30

Personally any gap of adults beyond 7 years is serious ick to me, power imbalance.

Dreamyposter · 02/07/2026 18:29

Obviously I'd have been horrified if my own daughters had bright home a 55 year old partner when they were 21 though!

If you claim your parents had been blissfully happy then I am curious why this would have bothered you so much?

saraclara · 02/07/2026 18:26

My parents got married when my mum was only just 20 and my dad 39. If there was any power imbalance I'm 100% sure that my mum was the one who had the power. She was a dynamo, and my dad a painfully shy geek.

Despite their polarised personalities, they were very happily married for forty years, until he died.

I know a couple who are 25 and 59. They've been together for four years. And to my amazement, they work fantastically as a couple. Both lovely people, and she is astonishingly mature and capable with her own very successful business. When I'm around then I totally forget that there's such a huge gap.
Obviously I'd have been horrified if my own daughters had bright home a 55 year old partner when they were 21 though!

Knittedfairies2 · 02/07/2026 18:26

I haven't come across this rule. If I had, I would have realised my boyfriend, now husband, was too old for me. We've been married for 51 years so I guess it doesn't matter now.

Dreamyposter · 02/07/2026 18:20

I dont agree with any rules but research does indicate that the larger the age gap, the more likelihood there is of divorce/split. The chances of divorce literally goes up according to age gap length

I am not quite sure why thats apparently "controversial"- it seems pretty damn obvious to me why that might be 🤷‍♀️

DeftGoldHedgehog · 02/07/2026 18:17

It was made up as an excuse for dirty old men to go after young women.