When I was married, I was part of a big group of couples / friends.
I split with my ex because he was abusive.
Every one of those friends knew what had gone on. And not one of them has ever said anything to him in the 2.5 years since we have split and still keep in contact with him. I would say, their contact is less, but still.....in contact. No conflict with any of them in any way. Yet they all know what he did, some even saw it.
I think the Nigella thing has brought this up for me - all the debates about why nobody intervened. And I realised not once have my friends ever really validated it by asking/challenging/ expressing disquiet to him.
I think I'm quite upset about this. I feel really let down all of a sudden.