My MIL has 3 sons (no daughters). My DH was the first of her sons to have children and we have 2 boys who she was very happy with when they were born.
She would babysit occasionally but made it clear she didn't want to have them overnight or do any regular childcare. I completely understood that - after all, she brought up 3 children herself so has done her fair share of childcare!
However DH's brother & his wife then had a little girl and MIL was overjoyed to finally have a granddaughter having never had a daughter herself. Suddenly all the previous rules she set were broken - she regularly has her granddaughter over to stay for weekends, does regular weekly childcare while DH's brother & wife are at work etc. etc. She went and bought all pink stuff for her house for when granddaughter comes to stay - pink highchair, bedding etc. etc.
Whilst I can understand her delight at finally having a little girl to fuss over, I feel very hurt that my 2 boys are so overlooked. We live closer to her than DH's brother so it's not to do with distance. DS1 even asked me recently whether MIL & FIL were his grandparents too or just granddaughter's.
Whenever I mention it to DH he just shrugs and says "well she's not perfect". He doesn't seem to be bothered by it at all so AIBU?