I think BrandNewHouse has the rub of it.
I was angry for years about the abusive and bullying behaviour of my inlaws. I did blame them. At our lowest point, when we were most needing some help, they accused us, isolated us and threatened us. and then tried to brush over it.
I was angry and hurt and it ate away and me and hurt my relationship with my husband as well.
It took 2 attempts at therapy to get through it. My lovely therapist let me get it all off my chest, and, as an uninvolved listener, was able to agree with my anger at our treatment....but then asked.....do you expect them to fix it? Do they care? Do they know? Will they admit it? What did their treatment of you actually cost you? And even if they were able and willing, what could they do to fix it?
She made me realise - they did not care or harbour any guilt and in fact had rewritten their narrative of events to alleviate any twinges of guilt they might have had.
What they had cost me was 2 years of my life, where I stayed, hidden and ashamed at rock bottom, too scared by their threats to get help for PND or my kids' SEN. And a fairly big tear in relationship with DH.
And then I realised there was nothing they could do to make amends for, or fix, that damage -we would have to do it. After a few years of hard work, we are back to firing on all cylinders, and working through all our mental health issues.
My therapist also helped me work out how best to continue (which, if any) relationships with inlaws that maximised protection of our mental health. So I worked hard to repair relationship with MIL, who is lovely despite her protecting of SIL, the family abuser, tolerate FIL who is a bit of an arse, and refuse to ever see SIL and BIL because I don't need that poison in my life. My DH takes the kids to a handful of family events that is a compromise that allows family peace to reign, lets our kids see their cousins, and also limits exposure to protect the kids from being hurt by how much closer grandparents are to their cousins, and means they won't inherit their disrespectful attitudes to me and DH.
So much happier that I took it into my own hands. They may have kicked us when we were down after decades of low level bullying but our mental health is our own responsibility...