Lots of background here so will be long, sorry.
DS is 10 months and MIL looks after him on Thursdays whilst I go to work.
DH and I separated in Dec because of his significant anger issues.
The whole family is the same. MIL is nuts (she was the one who used to steal swimsuits if you remember!) but does love DS and is generally fine with him.
SIL (absolute Fucking nut job) is currently visiting for easter. Every single time she visits, she is abusive. She shouts, she screams, she calls everyone a cunt in front of the children. She is completely unhinged.
I told MIL a while ago that I would rather DS wasn't there with SIL as I don't want him around all that horribleness.
She spoke to me, said SIL is much better, she's desperate to meet DS properly (she lives other end of the country) etc etc.
She has been down for two days, and today she spent the whole day screaming, smacked MIL round the face!! And has made my DSD (currently staying there) cry because of how hideous it is.
MIL says she is going home. She often does this though and they don't actually make her go, and she stays until the next incident a few days later.
I said to MIL that if SIL was there tomorrow I don't want DS there and can she let me know so I can get alternative childcare. I was very nice about it but said I just don't want DS around people like that, after all, that's why I left DH!
MIL thinks I'm being 'frightfully difficult' and 'stopping her having her grandchild' and 'contributing to an already difficult situation'
AIBU?