To think, 17 years on, my Mum could let this go?

Your mother is a disgrace and a bully.
Take a lot of space from her.
Your instincts did her a great favour and she uses it as a stick to beat you with?

She sounds toxic.
Stop putting up with it.

Even if you knew (not that you did) it shouldn’t matter. That was not your responsibility and secret to keep, tell, or do anything with. You simple were looking out for your mum. Their relationship was their problem.

You need to squarely tell her:
a) you were a child, even if you did have an intuition your dad had checked out of the family … what kind of mother blames a child for being in an impossible position like that? A bad mother, is the answer.

b) she is blaming you because she didn’t pick up on the signs of her ex’s unfaithfulness. It’s a way of letting herself off the hook and transferring emotional pain onto a soft target - her own child. That’s despicable.

I find this absolutely mental . The thought would never ever have crossed my mind to do this at 17 even if I knew about an affair. It’s extraordinary and she is so lucky. I mean even if you did know about it it wouldn’t be your fault and she shoudnt blame you anyway . A 17 year old is a child .

Your mother is a lunatic and you are a superhero. Imagine having that much intuition and the bravery to act on it at 17! I wish you were my friend 😀😀😀

She sounds like a vile bitter woman

You were being dead sensible. Everyone knows stuff should be backed up, few people do it...

My parents marriage was pretty bad when I was 17 too and you do get a bit "parentified". Sounds like you were doing the sensible stuff whilst they fiddled and Rome burned. I was also 17 when my BF's DH told me he was having an affair, trust me, even if you did know, it's an impossible position to be in.

"Look round, Mum, see this house and your current standard of living, how would it look if I hadn't backed the computer files up?"

The more time I spend with my unhappy elderly DM, the more I realise what she says to me about me is a projection of her own regrets/bitterness.

Good woman!

Don‘t expect her to change. Every time she brings it up, hang up the phone or walk out of the house. Don‘t let yourself be talked to like that any more.
It‘s perfectly normal to suspect someone is a liar without knowing what they were lying about.

Your mother should be thankful she had such an insightful, intelligent, clever and practical daughter!! She should be thanking you!

Your Mum has found a button she can push to get a reaction, and likely does so when she is triggered.

can you identify the trigger? Does she feel unsupported? Unsure? Alone?

I would try asking her about intent - what is her intent when she says this? What does she need from you?

and definitely a frank conversation that you have noticed the pattern, you can do nothing about what happened in the past or how she feels about that but that her inability to move on is detrimental to your current and future relationship with her- is that what she wants as she gets older? If she is a reader, try giving her one of the books on emotional intelligence and amygdala attacks - anything from Tackling your gremlin to Daniel Goleman on Emotional Intelligence could work (maybe read it yourself first and then pass on as a “I found this interesting “)

This is the kind of thing those quirky genius characters who get hired by the police as consultants do. I'd watch a few seasons of this show😂

On a serious note, that was really clever of you to do. I can imagine you must have a brilliant mind and your mum should be extremely proud and very grateful to you!
She's possibly embarrassed and jealous.

Say yes next time mum I get a flash of intuition that you might somehow get fucked over, I'll just allow it to happen ,so that you can't accuse me retrospectively of being untrustworthy. You would be a lot worse off if I hadn't been 'sneaky' as you see it at that time. Perhaps you could be a little bit more grateful rather than accusatory. I wasn't the one who did anything wrong. You weren't on the ball about your finances and Dad was prepared to have you over financially but yes blame the 17 year old who saved your arse.

You're an absolute legend Op. I could barely string a coherent sentence together at 17, never mind prevent my mum from being unfairly treated during a divorce.

This! It was such a clever and deeply thoughtful thing to do, maybe you wouldn’t have ever needed it but having the foresight to do it was amazing. What an ungrateful idiot your mum is. Sounds like she’d use just about anything she could as ‘proof’ you’re ‘no good’ op, I wouldn’t say having someone like that around was very pleasant, myself.

I agree with this.

I used to tell my mum she should leave my dad all the time when I was a teenager. Because to me it was pretty obvious he had absolutely no respect for her (or any of us) and was sneaking around.

Eventually when I was 16 he left her for his 25 year old assistant.

My mum spat at me one day “well at least you finally got your way”.

For some absurd reason she always blamed me for them splitting up.

Just tell her that you didn't know at the time that your dad was having an affair but that you now understand why he divorced her.

You mum owes you a bloody thank you. You saved her bacon big time. And even if you DID know about the affair, it was not your responsibility to get involved in your parents relationship and tell her. She would have probably blamed you for getting involved anyway.

Its sad that in hindsight, you would have been better off just letting your dad fuck her over twice.

Interesting that your Mum is able to turn this against you, instead the other way round.

Do people even have files and files of financial information stored in their computers? I certainly don't. That might be why I'm so poor!

Probably not now, but certainly they did in the days before the cloud. My father used to keep all the information about his shares and accounts on his computer.

I’m really fascinated by what sits in conscious awareness and what is unconscious. There is no doubt that was an odd thing to do, and one neither of you can make sense of easily. However it sounds as though your intuition or your sub conscious knew your dad was behaving secretively or strangely, or it would not have occurred to you that saving this info would be helpful.
your mum is clearly projecting anger with your dad onto the nearest person (you), and it’s totally not ok. I think you need to tell her how much it upsets you.
And trust your instinct! It sounds good.

What a mumsnet hero you were/are! At 17 too. I’m sorry your mum doesn’t know what a star you are. Maybe she’s still very hurt. Tell her one more time you didn’t know and going forward you would like matter dropped so you and her can have a good relationship. And then come on here from time to time and teach other women about ducks and rows . I expect it’s all “clouds” these days and not hard drives?

Well, she still clearly hasn’t gone over the divorce!
She’s been deeply unreasonable and very nasty. She should thank you, even if she does suspect you have been secretive, rather than throw it in your face.
Sounds to me like it is sit down with mummy time, one final time of explaining what happened, and a threat of your choosing around if she ever brings it up again then this will be the consequence

OP,

You are the scapegoat here.

You did everything right.

Well done, you! Xx