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Relationships

Mumsnet has not checked the qualifications of anyone posting here. If you need help urgently or expert advice, please see our domestic violence webguide and/or relationships webguide. Many Mumsnetters experiencing domestic abuse have found this thread helpful: Listen up, everybody

Husband suggested opening marriage and mentioned my sister, am I overreacting?

341 replies

Falalalalalala86 · 16/03/2026 18:38

Posting in relationships for more traffic as haven’t been able to stop thinking about this. It feels quite petty compared to some things on here but it’s been playing on my mind all day.

DH and I have been together 12 years, married 7. Two kids (9 and 6). Generally we get on well.

Last night after the kids went to bed he asked if we could talk. I assumed it was something normal (finances, holiday plans etc).

Instead he asked if I’d ever thought about “opening up the marriage”.

I genuinely thought he was joking at first but he was completely serious. He said lots of couples do it now and it can actually make relationships stronger.

I was really taken aback and said absolutely not. He then backtracked a bit and said he was “just curious” and we don’t have to do anything.

But it’s really unsettled me.

I asked where this had come from and he said it was just something he’d been reading about online.

Here’s the bit that’s bothering me though.

When I pushed a bit more he eventually admitted there’s a specific person he was thinking about.

And it’s someone I know.

It’s actually my younger sister.

Apparently she’d joked with him a few weeks ago about “modern relationships” when we were all having drinks and he says that’s what made him start thinking about it.

I feel completely weird about the whole thing now and honestly a bit sick.

He’s saying it was just a hypothetical conversation and I’m massively overreacting.

But I can’t get past the fact that he clearly has been thinking about my sister in that way.

AIBU to think this is completely inappropriate or am I turning something stupid into a huge issue?

OP posts:
TheSpottedZebra · 16/03/2026 18:39

A huge issue for me. As in, probably marriage-ending.

BellesAndGraces · 16/03/2026 18:40

AIBU to think this is completely inappropriate or am I turning something stupid into a huge issue?

Tbh I’m concerned you have to ask …

DirtyGertiefromno30 · 16/03/2026 18:40

YANBU this is a huge issue and is there something going on with your little sister already . Can they be trusted ?

AirMaster · 16/03/2026 18:41

This would be very hard to get past for me.

Aphroditesangel · 16/03/2026 18:41

I would not be happy and could not live with someone who I knew was thinking about shagging my sister.

tiptjestation · 16/03/2026 18:41

Hope they aren’t already at it ?

Livpool · 16/03/2026 18:41

Ugh that is horrible. That would be it for me

Jellytotsapplepie · 16/03/2026 18:42

Falalalalalala86 · 16/03/2026 18:38

Posting in relationships for more traffic as haven’t been able to stop thinking about this. It feels quite petty compared to some things on here but it’s been playing on my mind all day.

DH and I have been together 12 years, married 7. Two kids (9 and 6). Generally we get on well.

Last night after the kids went to bed he asked if we could talk. I assumed it was something normal (finances, holiday plans etc).

Instead he asked if I’d ever thought about “opening up the marriage”.

I genuinely thought he was joking at first but he was completely serious. He said lots of couples do it now and it can actually make relationships stronger.

I was really taken aback and said absolutely not. He then backtracked a bit and said he was “just curious” and we don’t have to do anything.

But it’s really unsettled me.

I asked where this had come from and he said it was just something he’d been reading about online.

Here’s the bit that’s bothering me though.

When I pushed a bit more he eventually admitted there’s a specific person he was thinking about.

And it’s someone I know.

It’s actually my younger sister.

Apparently she’d joked with him a few weeks ago about “modern relationships” when we were all having drinks and he says that’s what made him start thinking about it.

I feel completely weird about the whole thing now and honestly a bit sick.

He’s saying it was just a hypothetical conversation and I’m massively overreacting.

But I can’t get past the fact that he clearly has been thinking about my sister in that way.

AIBU to think this is completely inappropriate or am I turning something stupid into a huge issue?

It is a huge issue

he’s way off

and probably been watching porn online if he’s reading about opening marriages

I’d be completely devastated 😔

Imaginingdragonsagain · 16/03/2026 18:42

That is gross 🤢 she’s your sister. It would have been disrespectful and horrible enough if it was a friend, but he’s managed to make it even worse.

GoldDuster · 16/03/2026 18:42

Suggesting that he might like to shag your sister? That would be curtains for him.

JustAnotherWhinger · 16/03/2026 18:42

I’ve been a swinger for 20 years, as has DH, and even I’d consider any mention of a family member marriage ending.

It’s just inappropriate. And as a conversation opener it’s ridiculous. It’s ludicrous that he would expect any conversation that boils down to “I want to fuck your sister” could ever be remotely ok.

Gettingbysomehow · 16/03/2026 18:43

I would have gone apeshit.

Lastofthesummerwines · 16/03/2026 18:43

I don't think you can ever forget that conversion, it will always be there and it's probably the beginning to the end now. Sorry. Hope you're ok 🥰

FeelingSadToday1 · 16/03/2026 18:43

This would be marriage ending for me I reckon.

DRose3 · 16/03/2026 18:44

Yuck, there's no coming back from that - nor for me anyway. And no, you're not overreacting.

CharlotteRumpling · 16/03/2026 18:44

It's an indication of how much he has gaslighted you that you think you are overreacting.
That would be the end for me. Massive ick.

Farewelltothatid · 16/03/2026 18:44

That would be the end of my marriage OP.
Bad enough that he sprung the idea of an open marriage on you but knowing he wants to have sex with your sister, if he isn't already, is something you will never be able to get over

charlieandjenna · 16/03/2026 18:44

Absolutely right to be completely unsettled and upset about it. It would be bad enough him suggesting an open relationship but then to bring your sister in it. I think that would be extremely permanently damaging in any relationship. I’m sorry op, you are not wrong on this one.

Spirallingdownwards · 16/03/2026 18:45

Bin off his sorry ass.

Although I always like the tale of the husbands who want an open marriage and the wife has plenty of takers and he has none!

It wouldn't be for me and it seems it isn't for you either.

LilyBunch25 · 16/03/2026 18:45

Good grief. No. Divorce would be my next thought.

youalright · 16/03/2026 18:46

I could never forgive or forget that. That would be the end.

Devilsmommy · 16/03/2026 18:46

DirtyGertiefromno30 · 16/03/2026 18:40

YANBU this is a huge issue and is there something going on with your little sister already . Can they be trusted ?

Edited

This is what I wondered. Sounds like your sister has been flirting with him already and he's doing it right back. So trying it on for an open marriage would give him justification in his eyes. Fucking arsehole. This would be a marriage ending proposal for me. So sorry OP

WhatFlavourIsIt · 16/03/2026 18:47

Your husband telling you he wants to fuck your sister isn't petty. If this is real I would seriously consider leaving this relationship.

Untailored · 16/03/2026 18:48

God, some men are thick. Why on earth would he think it was a good idea to tell you he wants to shag your sister?

Pyjamatimenow · 16/03/2026 18:48

Those hills are for you, my dear.

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