My partner and I have been together 6 years. We have 4 children in total, two from my previous relationship, one from his and one together. We saw both family’s over Christmas with all 4 children and my family included my partners child in everything, including buying gifts. My partners brother and his partner however, failed to acknowledge my children (apart from the child me and my partner have together). I cannot fathom buying gifts for 2 children, and leaving the other two out. I will add that I know money is tight, but even just a tube of sweets so they felt included would have been nice. Note: this happens every year, and they even refused to invite my two children to their wedding.
AIBU to be frustrated about this?