'This' being that when I was 17, a few weeks before my Dad announced he was having an affair and wanted a divorce, I randomly saved all of his/ their financial information/ files/ spreadsheets etc from the family computer onto an external hard drive. When he then started being tricky/ outrageously dishonest about financial disclosure etc and had, it turned out, deleted all those files so she couldn't get a handle on anything, I gave her the hard drive and she and her lawyers were I think able to use the info about accounts he had etc to ensure he didn't totally screw her over.
She periodically uses this as evidence that I 'must' have known about his affair long before she did, and therefore should have told her. Or occasionally just as evidence of my cold, calculating and generally untrustworthy nature.
But - while I realise it wasn't exactly a great thing to do - I absolutely did not know he was having an affair, and have never really been sure why I did it at all!
The closest I can come to working out why is that I went in to the study to talk to him that evening and he was fiddling around with his spreadsheets, and he jumped and quickly closed the screen when I came in, as though he'd been doing something fishy. And that triggered a thought/ sudden insight that my Mum knew absolutely nothing about what he was doing with their finances, and that if he ever did leave or even die suddenly she wouldn't know what was what. So that evening after he'd gone to bed I just went down and copied all the financial files onto the hard-drive, and stuck it back in my room. I never looked at them or even thought about them again, until she was upset about all the financial stuff during their divorce. At the time I definitely didn't actually consciously think he WAS doing anything he shouldn't, and had no reason to distrust him. It was honestly just an impulse to do it, that for some reason I acted on rather than dismissing as bizarre/ thinking through that it was a bad thing to do.
Anyway this all got dragged out again today, as evidence of how I 'always' keep secrets and what an awful thing it was to have done. I know I shouldn't have done it, but also always feel slightly bitter that she happily used the ill-gotten information yet still has a go at me about it!
AIBU?