Bit of a long one this.
My Sil has a long and frustrating history of causing conflict within her family. All arguments and fallings out within my husbands family have centered around her (approx 2 or 3 incidents a year for the past 13 years I've been married).
At the moment she is estranged from her sister and mother, but has regular contact with us and her father.
She has mental health issues (which she acknowledges and is receiving counselling for) that stem from her childhood which she believes to have been abusive and neglectful. Social services did monitor her for a while, though no action was taken, and throughout her childhood her mother sought help from various agencies as she found it difficult to cope with her.
THere is massive history of things she's said and done and I won't bore you all with it (plus it depresses me to realise how long she/we have been going round and round in this situation).
We have good relationships with all members of the family and have made it clear that we won't get involved with any sniping or fighting.
In a recent hostlie exchange between Sil and her mother, she deliberately used some information she had about my husband to score points against her mother and undermine my husbands relationship with his DM. E.g ' x didn't even tell you x because he doesn't trust/value/ confide in you'. This information is extremely personal and sensitive and my husband did not want it to become widely known.
I'm hopping mad that she's betrayed DH to score petty points. Husband is sad and worn down by the whole situation.
Sil is blithely carrying on as though she's done nothing wrong and just sent me a message asking how I am. She is very good at rewriting history, her accounts of events always paint her as the reasonable party and omit anything she cannot spin (eg she recently physically assaulted her mother in an argument and totally glossed over it in her account of that incident).
A few days have passed since this incident, so by now she will have replayed it in her mind and convinced herself she was justified and correct. DH and I have not yet responded and have resisted the urge to reply with some home truths!
So, what to do? I would be more than happy to cut contact and so would my DH. Although we have to date maintained a reasonable relationship, It's not been a natural relaxed one as we're constantly wondering when the next 'episode' will occur. However, and this is the biggy for me, our son loves his cousin and would be really sad if he couldn't see him.
Any advice/ experience of similar situations would be appreciated.