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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

My sister, my bed, her ONS

118 replies

Laptopfangirl · 28/09/2026 16:36

I rent a flat in central London. I was away this weekend with work, and my sister asked if she could stay as she wanted to go out with some London friends. Fine. Not the first time.

I got back late last night and basically went straight to bed. This morning I woke up to discover a used condom in my bathroom bin. She brought a man back! She is single, so I can only assume it was a ONS. I have no issue with her having one night stands at all, but for God's sake clean up the mess! The bedsheets haven't been changed, the bin wasn't emptied. There were tissues in there as well which I presumed were just for makeup and regular cleaning but now God knows what else crosses my mind.

And to make it even worse I think (but can't be sure) that the condom was actually mine! Which would have meant them going through my bedside drawer (which also contains cash and God help me my vibrator!!).

I know my sister will consider it harmless but she brought a strange man back to my flat, shagged him, didn't clear up the mess and had me sleep in the same sheets!

Clearly AINBU to be slightly pissed off at this. But what level of anger is reasonable? A text jokingly calling her cheeky, or volcanic fury, or something in between?

OP posts:
Maggiethecat · 29/09/2026 00:41

Random321 · 28/09/2026 17:30

No need to go crazy, just ask....

"Did you really leave the sheets unchanged after you had sex in my bed?"

Would you really not change the sheets anyway as she was sleeping in your bed? That's odd too.

Condom should have captured most mess in fairness!

Change sheets after my sister slept in my bed? Nope, unless they were due for a change.

I expect that she showers before bed too and am not going to hold drops of night sweat against her 🙄

WeightLossGoal2024 · 29/09/2026 01:28

Yuck!
Definitely challenge her and get your key back

jeaux90 · 29/09/2026 07:25

OFGS OP just say “ did you have someone back to my flat this weekend?” I would assume she will be honest and then you can say “ please don’t do that again” this isn’t hard. …if she denies it you can ask why the empty wrapper then? Etc etc There is no need to go nuclear just be really clear about your boundaries in your own home.

dh280125 · 29/09/2026 07:30

I’d be furious

Blackbird2409 · 29/09/2026 08:03

No more stops for her!

socks1107 · 29/09/2026 08:15

She would’ve be staying again. Ever. That’s grim and a shows a real lack of respect

Heronwatcher · 29/09/2026 08:21

I would be very angry. Not just about the bed sheets but also he could have burgled the place/ made himself a set of keys! I’d be having a very firm conversation with her about respect and also telling her that should I let her stay again she’s never to bring anyone back without specific permission- if she meets someone she goes back to theirs or books a travelodge. I’d also get a ring doorbell.

LoafofSellotape · 29/09/2026 08:27

I would fit a Ring doorbell so you can see who is coming back to the flat. It's utterly grim and really shows a lack of respect.

Morecoffeeneedef · 29/09/2026 12:09

In your position, I would never again allow her to stay in my home when I was away , and would be more concerned about getting that message over than judging how angry to sound. She obviously thinks it's fine or she'd have covered up after herself. I don't think it's fine!

Laptopfangirl · 29/09/2026 12:41

I spoke to my sister. She confirmed that it was a man she knew already rather than incomplete stranger, but I don't think that makes a big difference. She said that she had indeed used one of my condoms, taken from the drawer. She said that she assumed he'd got rid of it after they'd finished and apologised that this was actually in my bin!

I was pretty clear that it was a bit horrible to come back to shagged-in sheets and a used condom in the bin. She said she was really sorry.

OP posts:
MadMAGA · 29/09/2026 12:45

I wouldn't care about the ONS but I'd expect to come home to a clean bed and an empty bin. She's apologised so will presumably bring her own condoms next time. Just make sure she knows where you keep the spare sheets and bin bags.

ToadRage · 29/09/2026 12:49

Is the money gone? Obviously I would be unhappy about not changing the sheets, when my husband and i borrowed my brothers flat I put the sheets in the wash and remade the bed before we left which is just common courtesy. I wouldn't have a problem with her using one of my condoms, I'd rather that than having unprotected sex but since you said you keep money i that drawer i would only be super pissed off if that was gone.

DuckbilledSplatterPuff · 29/09/2026 12:51

Ring Door Bell.

BMW58 · 29/09/2026 12:54

If it were me I'd let it go this time, but if it ever happens again you'll be taking back the key permanently.

And do install a ring doorbell so you'll know.

The trust is broken.

DoloresDelEriba · 29/09/2026 13:18

She should have changed the sheets and cleared bin etc. I have a similar arrangement in London and don’t think I would have a ONS there. Mainly because I’m older and those days are probably behind me. BUT if I did I would make sure not to leave a trace of it…

ps also horrified at idea of vibrator sharing and amused at pubes. I’m in possession of plenty still! 🤣

godmum56 · 29/09/2026 13:47

Myli1 · 28/09/2026 18:08

Well of course it’s not an easy thing to think about, but unfortunately I think you’re going to have to have some sort of dialogue with your sister to clarify what has gone on whilst you weren’t there, and perhaps suggest some boundaries you would like her to adhere to. I’d try and keep it lighthearted if possible though, you don’t want to end up with some longstanding feud.

"suggest"????

godmum56 · 29/09/2026 13:48

Laptopfangirl · 29/09/2026 12:41

I spoke to my sister. She confirmed that it was a man she knew already rather than incomplete stranger, but I don't think that makes a big difference. She said that she had indeed used one of my condoms, taken from the drawer. She said that she assumed he'd got rid of it after they'd finished and apologised that this was actually in my bin!

I was pretty clear that it was a bit horrible to come back to shagged-in sheets and a used condom in the bin. She said she was really sorry.

yeah I bet she wouldn't have been sorry if she hadn't been caught

Sunsunsuns · 29/09/2026 14:05

Laptopfangirl · 29/09/2026 12:41

I spoke to my sister. She confirmed that it was a man she knew already rather than incomplete stranger, but I don't think that makes a big difference. She said that she had indeed used one of my condoms, taken from the drawer. She said that she assumed he'd got rid of it after they'd finished and apologised that this was actually in my bin!

I was pretty clear that it was a bit horrible to come back to shagged-in sheets and a used condom in the bin. She said she was really sorry.

We teach people how to treat us.

You are very generous towards your sister and that is what you come back to.

So grim.
I would think it's worth rethinking your generosity.

She is extremely disrespectful of you and your home.

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