To think my DM just needs to stop

Jesus, that is not OP's responsibility.

OP, I would explain to her that if these events are still playing on her mind decades later, she needs professional help. She can get referred for six weeks talking therapy via her GP or in some areas via self-referral. Offer to help her access that and then tolerate no more repetitions.

I’m kind of in two minds here.

firstly, if it’s literally the same stories over and over again, in my mum this was the beginning of dementia.

if not, then I am sort of in the same situation. I left a twenty year marriage due to violence. It us genuinely quite hard for me to never mention him at all.

fir example we were away over Christmas and I remembered a time we’d done something in the past when they were kids and I have to remember NOT to say “hey do you remember doing this as kids” because it would remind everyone of him.

sometimes my filter slips and I do say “hey we did this”.

it’s not out of malice. There’s just a massive period of my life I can’t talk about to my kids.

From your update OP it’s possible that she is not capable of having enough empathy to change. My husband’s sister was similar and got worse as she got older. It’s tough.

I’ve been here with a family remember and it’s horrible. She sees her own suffering and not yours. You can’t fix her. You can move around or away from her but ultimately there is so fix unless she does the work to process her situation. It sounds like she’s settled into the victim role fairly well so I’m not sure she can change.

Completely agree. It is not benign for the OP listening to all of this bad mouthing of her father. It upsets her greatly. She does not need to set herself on fire to keep her mother warm that is completely unfair. Her mother needs to get appropriate support herself. Families should have healthy boundaries and that is not happening here.

Not necessarily. She could have felt trapped. Been coerced. Sounds like OPs dad was a bit of a twat.

She may have felt her life with this man was wasted.

I'm sure she's happy that she has her children who she single handedly brought up by the sounds of it. But I do get it OP.

She needs professional help and is obviously not able to just shut up and move on. I agree you shouldn't be the one to give her the help she needs.

We all feel sorry for her. But going on and on about it to her daughter is unlikely to be helping her. And is obviously distressing her daughter.

If we want a better outcome for both of them we should not be guilting the daughter. We should be suggesting ways in which the daughter can protect herself first of all,and if it's needed and feasible, directing her mother towards more constructive ways to deal wih her residual distress.

It’s really not as simple as leaving the past in the past when it comes to deep rooted trauma but you’re not the person she should be off loading to. She needs therapy.

Aside from that, what does her life look like outside of her family? Does she have a job? Friends? A social life, hobbies and interests?

I agree with this. It was a long time ago but perhaps being at op’s house brings the memories of how your mum parented and struggled alone right back.

There can’t be many people she can speak to about this.

However op, equally, I understand you wanting your mum to move on and that’s the crux of it really isn’t it? Someone who is content and happy in the here and now doesn’t usually feel the need to constantly revisit their old life. Does your mum need more new experiences to block out the old? What are her hobbies? How does she spend her time?

You are conflating two different things. One is wanting your mother to move on. The other is not wanting to hear stories about your father. You can't do anything about the first but you can about the second. You have asked your mother to stop telling you these stories so you need to get more assertive. As soon as she starts on a story say you don't want to hear it and then hang up, archive the chat, leave the room as applicable. Go and do something else. She should learn fairly quickly that you are not going to listen. If she still doesn't stop then you need to take some space away from your mum for a while.

She needs counselling, she’s trying to use you as her therapist but understandably that’s inappropriate and upsetting for you.

Can you write her a letter and explain how you feel? Be compassionate, she sounds like she is stuck in the disappointment of her own life.

This is a really important point, because it's abusive towards OP. Been there, done it, got the t-shirt. Also note it is women who end up in this pseudo-therapist role for the parents, rarely the men, so it's another expected form of emotional labour expected from females.

“Mum, enough! You won, you’re here and he isn’t.”

Stand up and walk away. Every time.

As someone whose dad experienced childhood trauma that he hasn't processed, it's likely that the OP has been fulfilling the role of therapist for her DM for a long time and has had enough. OP, it's not your job to hold space for your mum's experience. Next time she brings it up, say you'd rather not talk about this and if she wants to talk about it with someone, suggest she finds a therapist to do so. If possible for you, you could offer to help her find a therapist or help pay for it. It's not uncaring to set limits on how much or what kind of support you can give.

This. The next time she does it, explain that you cannot listen to it any more, and give her the contact details of a good local therapist.

Even consider helping her pay for some therapy if she can't afford it.

There need to be consequences for her bringing it up - leave if it happens or take her home.

Yanbu.

My dm brings up my dead dad (they were divorced, he was awful) randomly and its just arresting.

I'm living my nice life in my nice kitchen with my nice kids talking about what nice thick hair my dd has and boom! He is back in the room as my dm is chuntering on about what thick and lovely hair my dad had 😵‍💫🤯

I hate it

I find MN so weird about this kind of thing. Half the time it's "your only role is to support people!" versus "they are toxic, go NC".

Anyhow... it sounds like she is experiencing some kind of trauma and cannot help the way she is behaving. She might also be of an age where "getting therapy" is alien to her.

Maybe, rather than wait till she starts, you can approach it proactively and say "Mum, you know you always...
I find that really hard when you do that...
I think it might help if you talked to a counsellor".

She may well say no, though.

She has proven she doesn’t care about your boundaries. You need to stand up and leave every time. My nan does this, I refuse to discuss my mother with her but she still tries on occasion to open a conversation about my mum with me. I now stand up and walk to the kitchen to make a tea and when I get back I ask about her friends/various appointments etc. She tries much less now.

Hard disagree.

She is her child, not her friend or therapist.

Don’t help her to process it - encourage her to get therapy.

She needs to process it (or just shut up about it to you), but you shouldn’t be the one to help her. You’re already upset by her frequent allusions to the past.

I grew up in a similar environment and also had to listen to my mum badmouthing my dad. They don’t realise how much it can hurt you. You need to tell her very explicitly, as a previous poster suggested.

she must have loved him at one point to marry him and have 3 children.,