My sister in law has always been bitchy and often falls out with members of her family. I try to stay out of it but stuck up for others when I can. However, I think on reflection she's been allowed to get away with this by the family because everyone is scared of 'setting her off'. I always assumed she probably said nasty things about me behind my back like she did with every other member of the family but only found out recently that she had said things about me. She got really drunk a couple of days ago and slagged me off to my partner. I was cheating on him, I was controlling, my house is awful and I'm neglecting my DC. I confronted her but she denied it all (this is her MO).
I spoke to my other DSIL about it (partner of my partner's brother) and I commented 'she does it to everyone, I've heard her talk about every single member of the family'. So DSIL asked had she said things about her and I was honest and told her. I thought she would keep it to her self as we know other sis-in-law will just deny it. But she didn't she also confronted her (and of course she denied it). So then first sis-in-law immediately phones me to confront me. DSIL2 was with me so it confirmed that SIL1 had said things. It was basically she said DSIL2 was neglecting her 2 DDs.
She then sent me loads of abusive messages. Insulting me about my weight, my house, anything she can think of. She told me I'd 'bought my way' into being DSIL2's DD's aunty (when really they were nothing to do with me, she said.) Actually, I've just always been there for the girls and both their parents and we are really close. She told me I'd really pissed her off and 'started something' and she was going to report me to social services and get my DC taken off me.
I have a theory that she likes to think everyone else is neglecting their DC because she did and her DC were taken from her. I don't think she deliberately sets out to hurt anyone but that is the consequence of her behaviour and I think it is finally biting her on the bum. But honestly, after everything she has said I don't think there is any way back. I've always tried to get along with her, I've never judged her, always supported her. But now I just want nothing more to do with her. AIBU?