Feeling hurt, should I say something?

Pat123. Thank you. So sorry you are lumbered with a horrible SiL. Do keep an eye on your brother as best you can. He may have a difficult life. At the extreme end one needs to just be aware that the narcissistic types who wreak havoc in people's lives always take their partner almost into captivity and cut them off from their family and friends. They also tell lies about them, well, they lie all the time actually. Not that your SiL is on the extreme end but she is keeping your brother away from his family... very unhealthy. What amazes me is just how common this is becoming! Honestly!

Well, although two wrongs don't make a right you could consider arranging an all female event yourself; spa day - afternoon tea - theatre trip etc and exclude the sister-in-law.

Alternatively, be the bigger person, rise above it and don't let her see that she gets under your skin. Many of us have that someone in the family that behaves just the same as your SIL, yes it's hurtful but stressing over it simply makes us miserable

I was hurt because I was the only aunt not to be invited, but the others are my SIL’s sisters.

Hang on OP, was this a get together held by SIL’s side of the family? Do you even know if it was organised by your SIL? Could one of your niece’s aunts have organised it as a treat for their side of the family?

If this was a celebration your niece was having with the other side of her family, then I’m not sure why you’d be invited to be honest. There isn’t anything wrong with socialising with each side of the family individually. In fact, we can’t all be invited to every social engagement all of the time otherwise every get together would be the size of a wedding!

I wouldn't walk on eggshells for her. I would say what I wanted, and if she didn't like it, oh well. Except for being "tactless." IMO, you really should try to watch that. But if that isn't the issue w/ her, then no worries.

If you simply can't tolerate her harsh reactions (and who could?), then I think your inclination not to be around her is correct, and you should avoid it. So maybe it's just as well you weren't on that girls outing, and sorry to say, maybe SIL feels the same way about being w/ you. The two of you may just be oil and water. Generally speaking, in fact, I would say to steer clear of her steer clear of her even if/when you have to be at the same event and try not to get into discussions w/ others in front of her.

But I just saw the post about these aunts being SIL's sisters. So perhaps it was mostly for her side of the family? Your DB (dear brother) told you she's only comfortable w/ them. Believe him. That probably explains it. Now please put it out of your mind and look forward to enjoying that party!

Phew @ Tonk & Starlady!

Was wondering for a bit why I was the only poster thinking its okay for adult siblings to get together with their kids without always being obliged to invite all inlaws every time!

It seems the OP has form for getting the hump at not being seen as one of the sisters, when she isnt one! Shes extended family and is invited to extended family things. The SIL os allowed an "inner circle" we all are!

I think the advice given to ask her calmly and politely what the problem is may be the best solution. If she can’t answer I’m the same vein then the problem is hers. Leave her to it. Protect yourself. You have been hurt, understandably so. Make this one attempt when it feels the right moment for you, and as I suspect she won’t be able to answer in a kindly or open way- then avoid her at all costs. Your well-being is more important. Don’t feel you have to do anything that makes you uncomfortable for the sake of ‘the family’ Time to put caring for yourself first. I hope this is of some help.
Courage! Good Luck! At least you will have tried.