As background, my BiL (husband's brother) and his wife are having issues within their marriage
So, it was my birthday recently. I received a lovely card from them (SiL is usually the one to organise, I know!)
In the card, she also enclosed a letter detailing all their troubles and how awful their situation is (which it is, of course)
AIBU : no issue here, you're being precious 😁
AINBU : she could have sent it separately