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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:
aWeeCornishPastie · 16/03/2026 22:36

Wtf no way . Yes divorce material right there

FloofBunny · 16/03/2026 22:37

NewYearNewMee · 16/03/2026 18:51

I’d be getting divorced 🤷🏻‍♀️ and also asking my sister what the hell she had actually said!

Wanting to have sex with my sister? Thinking sexually about my family members? Disgusting, gross - ewww?? My BIL is like a family pet, he’s just there at family gatherings and gets in photos - I have never ever ever even considered that he might have sex with people 🤮 my nephew was an immaculate conception!

My exact attitude to my BIL! 🤣

Spookyspaghetti · 16/03/2026 22:38

Force him to watch the Louis Theroux Manoshere documentary with you so he can see how truly sad the open relationship bros are.

trumpisruin · 16/03/2026 22:43

Ilovepastafortea · 16/03/2026 19:55

I agree with PP. If my husband told me that he wanted to have sex with my sister that would be the end of our marriage.

As for 'open marriages' so not a good idea, someone is going to get hurt & it's all about the man's ego. IMO it's like having a whole shop full of cakes & wanting to take a bite out of each one.

<exits to puke>

All about the man's ego ... until he realises that it's easier for women to find attractive men for casual sex than it is for men to find attractive women for same.

Missj25 · 16/03/2026 22:44

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?

Your husband is a Dick .
He suggested fucking your sister to you .
I don’t think I could ever, ever get past that .
Also you turned down his suggestion of an open marriage , so I believe he will cheat once given the opportunity if he hasn’t already .
Sorry OP , it’s just shit to be fair .

RisingSunn · 16/03/2026 22:46

Well surely this is the end of things.
I’ve really heard it all now.

Dweetfidilove · 16/03/2026 22:52

Joking my ass 😞.
If you're not going to leave, tell him you're open to a foursome if you can have his brother- joking.
Although the wretched fucker may actually be open to that. Yuck!

watchingthishtread · 16/03/2026 22:59

Tell him to stop watching porn.

Shitmonger · 16/03/2026 23:02

Christ, the misogyny is rife in here tonight. OP clarifies that her sister doesn’t like him and isn’t interested and yet we still have pages of people blaming her or insisting that she’s sleeping with him. Some of you are either watching too much television or are simply delusional and salivating over making someone’s real life worse. Hmm

Purplerubberducky · 16/03/2026 23:03

The marriage would be over. No discussion. No going back

YourWinter · 16/03/2026 23:05

I would be actively planning to end the marriage. Sorry OP. He’s warned you he wants sex outside your marriage and now you know, he will pursue it, probably not with your sister. Just another man with his brain between his legs. Ugh.

shuggles · 16/03/2026 23:07

@Falalalalalala86 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 have basically no experience with relationships or dating, and even I know that a woman making a joke is absolutely not an invitation for sex.

Is he really socially inept? How can a man be alive for so long and not understand that women making jokes and being friendly has got nothing to do with women wanting sex?

Purplerubberducky · 16/03/2026 23:08

Even without the sicko mentioning your sister. I’d get rid. He will only get worse as he gets older. He won’t change.

nocoolnamesleft · 16/03/2026 23:11

He's letching over your sister? And wants your permission to shag her? Run for the hills.

Pistachiocake · 16/03/2026 23:11

He presumably said some version of forsaking all others during the vows? Unless it turns out he has a medical issue that affects his brain, or has a very strange sense of humour, I'd be saying there's no marriage to open.

And if your sister has in any way considered it a possibility, she'd be out of my life too.

topcat2026 · 16/03/2026 23:11

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.

He’s a lying toad, he’ll have been fantasising about her long before then. You can do much better than this prick.

OlderGlaswegianLivingInDevon · 16/03/2026 23:11

I would have started divorce proceedings today.

ACynicalDad · 16/03/2026 23:13

That’s grim. Yuck

Bertiebiscuit · 16/03/2026 23:17

Ugh he's disgusting. Kick him out and divorce him, also try and find out what he may have already been up to with your sister. 🤮🤮🤮

Frugalgal · 16/03/2026 23:22

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?

The only shocking thing here OP is the degree to which you are second guessing your reaction and underplaying this horrible thing he's done.

What's happened here is he wants to shag your sister so much he has got to the point of openly asking for it. He's thinking he'd never be able to get away with doing it on the sly as she is your sister, so he's just gonna come out and ask for it.

Of course, it would only be an 'open marriage' in that in his fetid little fever dream he would be shagging her while you were not shagging anyone.

Can you imagine what he'd be saying if you told him you wanted to 'open the marriage' so that you could live out your fantasy of fucking his younger brother?

Get shot of the creep.

Bertiebiscuit · 16/03/2026 23:31

Read Gisele Pelicot "Hymn to life". Her ex husband began his abuse of her after having suggested an "open" marriage, which of course she declined. Perverts gonna perv

2catsandhappy · 16/03/2026 23:42

He is as thick as the two short planks I'd hit him with.
No coming back from that, no pretending, no amnesia and no forgiving either.
I hope the last sound he heard in your house was his suitcase hitting the back of his head.

FFSToEverythingSince2020 · 16/03/2026 23:43

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?

I mean, the truth is that if you’re already in a monogamous marriage for years, you only “open” it if something is lacking. And it would need to be a joint decision. At the moment he’s just, what, obsessed with your younger sister??? So it’s not even that you don’t have an active sex life; he just wants an excuse to play away with just one person in particular. Also, you know your sister - has he taken this single comment about “modern relationships” out of context???? I talk to a lot of my friends about sex, but I don’t want to have it with any of them!

Leaving that aside, does he even realize that an open marriage would mean you having sex with other people? My ex wanted to “open our marriage,” because I was too sick for sex and had gained weight. I wouldn’t have been well enough to be with anyone else. He used it as an excuse to fuck one of my best friends, then divorce me (while I was STILL sick), and married her. So yes, when men say shit like this after years of a monogamous marriage, it almost never works out well (yes, I know - cue tons of cool “women” with stories about how great it was and it livened up their dead bedroom, even though the very term “dead bedroom” is an invention of the manosphere - it usually means a woman is too exhausted, mentally and physically, for sex, and instead of helping her, the man complains to predominately other men online).

FloofBunny · 16/03/2026 23:57

PyongyangKipperbang · 16/03/2026 22:34

I disagree.

I think she needs to say "Ok babe" and help him set up his Tinder, whilst also setting up her own. And then sit back and watch the dates that fail to flood in for him and her phone blows up.

Haha, yes that too!

Ghostorno · 17/03/2026 00:03

He wants an open marriage and admits he’s got designs on your younger sister…warn your sister. This isn’t going to end well for your DP.