For not inviting SIL on holiday?

What if DB was the one who wanted his wife to be included? He might try to guilttrip you into taking her next time by saying she was upset she couldn't come. Maybe sil said something like "oh, that sounds so lovely, they must have had so much fun" and DB thought you ought to include her next time.
3rd hand comments should be met with suspicion. I would talk directly with sil and ask her if she was disappointed you didn't invite her. She will be mortified either way but atleast that will be the end of it.

For goodness sakes. @7yo7yo why on earth should she invite her? I don't invite my sister if I want to go away with my best friend, and I don't invite my best friend if I want to go away with my sister. And if I want to go away with one sister I don't feel obliged to invite my other sister! The SIL is not even that close!

I have five sisters-in-law, two married to my brothers and three sisters of my husband. I get along well with all of them and am particularly close to two of them. They all have sisters of their own. Would it occur to me for a single minute to be upset that they went off on a getaway with their sisters and didn't invite me? No, I would not. Just as they would not get upset if my sister and I went away for a break.

OP, you are definitely not being unreasonable.

I would tell him a) that you are not obliged to invite everyone every time. This was simply a trip for you and sister, and b) it was a two bedroom place. Also, c) you will organise trips in the future inviting whomever you wish. Sometimes you will invite SIL, if you feel it appropriate. Sometimes you won’t. Your Bro isn’t going to be expecting “Why didn’t you invite us?” Phone calls every time he or SIL puts photos on Instagram, is he? You can start….

Your SIL’s being weird. It’s perfectly normal to do different stuff with different people. Nobody is entitled to be invited to everything.

Is just let him know that this wasn't a 'girls trip' but a 'you and your sister' trip. And that if you'd wanted a third person it would have been him, your sibling, rather than someone who doesn't have the shared history.

If it were a siblings trip surely you'd invite your brother not his wife?

It's a totally different dynamic. I love my dsis. We share a lifetime of childhood experiences and interests, while my relationship with my sil is one of a friendly acquaintance. I'll happily share a couple of hours shopping or a lunch but that's enough.

Your Db is being unreasonable.

If you feel comfortable with a single overnight I think that's lovely.
However, id be making clear to bro that communal and familyal at different

It would make so much more sense if he said HE was disappointed not to be asked with you!

Your brother is an absolute dick for even telling you this.

I’d like to know the answer to this. Which of his in-laws does he invite to places, holidays in particular

Sounds like your SIL is a12 yr old. I would ignore. I’m glad you had a good time with your sister.

Does he invite your partner to go away with him?

YANBU! Of course you can have holidays with your sister and not need to take SIL along too.

You’re siblings. Anyone else changes the dynamic of the trip. Sometimes that’s a good thing, sometimes you just want to spend time with your sister.

This. You absolutely do not and should not be expected to take any of your in-laws on a holiday you’re going on with your sister!

Bonkers. Of course YANBU. There is either something more to the dynamic, DB has misinterpreted or your SIL is a drama queen.

you of course can unashamedly depend time with your sister! People are so weird 🤯

No you're not wrong. You probably have a different dynamic with each one and like you said fine for a shopping trip together or a lunch etc...but a holiday is different. I am close with my sister and have a good relationship with SIL too. When there is a family gathering all three of us get on great but I know on a holiday I would be the middle one and their relationship together is not as close as mine with each of them. So it wouldn't feel the same. My SIL certainly would be upset about us going on holiday together, I find that really odd she doesn't understand that.

Is your SIL an only child? Maybe she is looking at being more like a sister to you and your sister as she doesn't have a sister of her own to go away with. Not that that excuses them guilt tripping you. You absolutely should not have invited her along just because she's you SIL.

Maybe an overnight spa break is more suitable to invite her to but not a holiday you planned with your sister.

How ridiculous, YANBU

Of course YANBU.
Your SiL is being odd.

Perfectly fine to go away with your sister - the relationship is completely different.
It wouldn't occur to me to want to go away for a week with my SiL and her sister, and I like my SiL a lot. We do occasionally meet up for lunch / theatre / coffee / concert just me and her, but I wouldn't expect to spend a week's holiday with her.

I think I'm SIL type here. I was hoping to have a more sisterly relationship with my sil's and would have welcomed that but it just didn't happen like that,

But that's just a feeling I have in my head. I wouldn't dream of saying it to him. He shouldn't have said anything to you because you can go on holidays with whoever you like.

Your sister-in-law is a self-absorbed drama queen. She really has no understanding that sisters may want time to themselves? Good grief.

It's perfectly fine to go with just your sister. I'm not sure why SIL thinks she has reason to be included or to be upset that she wasn't included.
I'd be inclined to tell your brother that you both do like her and enjoy her company, but also want to continue doing things just as sisters every now and then.

Than no YANBU.
if there was a tradition of you all going away or common interests I would understand her hurt but you are still allowed to holiday without her.
If she hasn’t directly said anything to you I would ignore DB. She may be hurt but understand.