I am an adult with my own dc, my mum has younger children (my half siblings). My dd and my half sister are a similar age (11+12).
My mum is an oversharer and has history of not respecting my sisters privacy. I don’t mind her telling me things because I’m an adult and can keep a secret but I have asked her over and over again to not tell dd anything which she was respecting.
My sister has had some, at least for her embarrassing medical issues recently. Mum came round and tells me and dd all about it. I specifically told dd that she forgets about that and never repeats it which she promised to.
Next day she goes and messages my sister about what she was told.
Normally we take my siblings away with my dc in the holidays, my sister now doesn’t want to come obviously as she is upset that dd knows about her personal problems.
I’m really disappointed in dd for being unkind and breaking our promise and the only fair resolution i can think of is that I tell my sister a similar embarrassing story about dd so that she can experience what it feels like and so my sister isn’t in such a vulnerable position.
Wibu to? I know it’s unkind and makes me as bad as my mum but I don’t know what else I can do.