To ask why my MIL hates this woman so much?

[Madridinmymemories]

I love my MIL, but there's an ongoing issue which I think she needs help with. Last year a couple with children moved in next door to her. The husband was in the army and left to go on service pretty soon after the move, the wife started having her toyboy over to sleep, subjecting PIL to some pretty noisy sex! Whether they got caught or fessed up it ended with the husband moving out and the OM moving in.
MIL absolutely hates this woman. It's really affecting her life. She wants to move ASAP which won't happen as they've spent a lot of money on the house in last few years. She refuses to go out in the back garden as she might see 'her' over the back fence and have to pretend to be nice.
Behind all this though, is pure rage. Today it was the fact that the couple were sitting in the front garden and he was touching her leg and kissing her. I said maybe they should have done it in the back garden, although I didn't really see the problem. MIL was shaking with rage saying 'they shouldn't be doing it at all, anywhere!' I feel like if she let go of a lot of this then her life would be happier and less stressful.
We've all know people whose morals haven't matched our own. I used to work with a girl who regularly cheated on her dh, even inviting the two men to the same pub to test who loved her more You just have to let them get on with it and hope that karma exists. I try not to judge as no one knows what goes on in a relationship apart from those two people.
Any advice welcome!

I would guess that the situation reminds your mum of someone else who cheated and destroyed the life of somebody your mum cared about. She is having an emotional reaction, that must be really hard.

@MRex I agree but her reaction seems to be stronger because sheis a female cheater. By all accounts her father cheated on her mum lots but he's still lauded as this great dad and family man which I've always found a bit

(Even though it is absolutely none of your MIL's business) she needs to find a way to forgive the neighbours and move on. All this rage and upset are not impacting the neighbours, it is only affecting your MIL. She can carry on nurturing these feelings and allow them to make her miserable for years to come, or she can seek help and learn to enjoy her own life. Would she consider counselling at all?

its laughable. She hates her and avoids her yet pretends to be nice! Does she always make drama. Either she has been cheated on or possibly unknown to anyone else she has cheated in the past. Either way its something that affects her in a personal way yet shouldn't.

Why does she have to pretend to be nice? She should just allow her contempt to show.

her reaction seems to be stronger because sheis a female cheater. By all accounts her father cheated on her mum lots but he's still lauded as this great dad and family man which I've always found a bit

Perhaps her way of coping with her father's emotional abuse of her mother was to blame and demonise his female partners, so she could scapegoat them and let him off the hook? Much easier, given she presumably never knew them at all, or at least not well, whereas her father she loved. If that's how she coped then perhaps the woman next door stands, in her mind, in for the women with whom her father betrayed her mother.

Could just be irrationality on her part, or some other trigger, but I do wonder.

Your MIL is taking out all of her baggage on her neighbours. People who don't impact her life whatsoever. She needs therapy because this is WAY out of control.

What advice does she want? Move if she doesn't like it. Knock on neighbours door and ask them to not touch (they'll tell her to fuck off).

Also is your MIL hanging off the top of a ladder and shaking in rage? Or just pressing her nose against an upstairs window?

Maybe you could ring the daily mail and ask if they're keen to photograph your neighbours kissing in the garden whilst you spy on them from a bush🙄

Affairs, low morals and outrage. 🤔 Warn your MIL she needs to keep an eye on FIL. Does he go running locally?

What perfectstorm said above.

I think perfect storm's analysis is probably true.

You, or perhaps your husband, need to have a conversation with her about why she finds this behaviour so completely unacceptable in her neighbour whilst it was apparently acceptable in her father.