My step sister is getting married in august, the invites went out a few weeks ago and it's become clear me and dh aren't invited. I asked my mum about this and she confirmed it, said she had asked my step dad about it and he just said he didn't want to get involved.
Mum and him got together when the kids were older teens/young adults so step siblings have never lived together but we've always got on. We all live in different cities and even countries but we have get togethers at Christmas etc
The wedding is abroad and child free (we have a few kids) but one of the other step siblings got married last year and it was child free and we went and had a lovely time, we had zero problem with this.
It's become clear also that it is going to be a very 'instagramable' wedding and we just don't fit in, all their friends are glamorous and we are homely and overweight.
They have invited family of parents, step parents, full siblings and their partners and about 40 friends according to my mum but we haven't made the cut.
I know the usual mn attitude is people can invite who they want to their wedding but Aibu to feel sad and angry at not being invited?