'My daughter is cheating on her husband and I'm helping her get away with it.'

"Everyone thinks my daughter has the perfect family life — married for more than a decade with two charming children and a beautiful home," Sally* wrote in a piece for The Sun.

"But only I know that she has secretly been cheating on the father of her children for the past two years. And I'm not just willing to help her in her deception, I'm absolutely delighted about it."

From the moment she met Dave* in 2013, Sally took a disliking to her daughter's partner, describing him as "brash" and "full of himself".

Watch: Woman discovers husband cheated with BFF. Post continues after video.

She hoped things would "fizzle out". She thought her daughter, who she said is clever and successful, with a job in PR, would "come to her senses". But two years into the relationship, Dave proposed while the pair were in Paris.

Sophie* knew her mum wasn't a fan of her partner.

At first, the 35-year-old would make excuses for what Sally deemed questionable behaviour. But when Sophie fell pregnant, Sally "realised with a sickening jolt that Dave was here to stay". The couple now share two young children.

Giving up her career to look after the kids, Sophie "struggled" alone, shared Sally, as Dave would go to the pub after work, and to the golfing range on weekends.

"Outwardly, they looked like the perfect, happy family — but I knew Sophie was beginning to resent him," Sally told The Sun. 

Then Sophie returned to work part time — and things changed.

Sally noticed her daughter started "making more of an effort" with her appearance, and a name kept popping up in nearly all of her work stories: Ben*.

"A glimmer of the old Sophie returned," Sally told the publication.

When Dave was away one weekend, on one of his golf trips, Sophie asked her mum to look after the kids. She was going out for a drink with Ben. Afterwards, she came home happier than Sally had seen her in a while.

Happy to see the shift in her daughter's mood, Sally offered to watch the kids if ever she wanted to go out for a drink with Ben — and Sophie took her up on her offer. Eventually, Sophie admitted to Sally the pair were having an affair. 

"I wrapped my arms around her when she left and promised that her secret was safe with me," Sally said, telling her daughter, "If this is what it takes for you to be happy, you know I'll support you. Dave doesn't need to know."

That was two years ago. Now, every time Dave is away — usually once or twice a month — Sally babysits her grandchildren.

"It's nice to see her smile again," she said. "I feel like I've got my daughter back."

As famous couples' therapist Esther Perel previously said on Mamamia's No Filter podcast, cheating is "the quest for lost parts of one's self; it's the quest for a sense of aliveness, for vitality.

"It's a quest to reconnect with the unlived lives."

And Sophie's newfound happiness certainly seems to reflect this sentiment — although if what Sally says is an accurate portrayal of their marriage, it does sound like Sophie and her husband have some issues that have developed slowly across the course of their relationship.

As couples' therapist, relationship counsellor and sexologist Isiah McKimmie previously told Mamamia, "Psychologist Shirley Glass and therapists like Dr John and Dr Julie Gottman talk about a slow disconnection in relationships that often builds up or creeps in slowly. This is what ultimately can lead to infidelity.

"I certainly have never seen a couple who have experienced infidelity, where there weren't some underlying issues with their connection, their communication or their sexual intimacy."

While Sally said that she would like to meet Ben, she feels the less she knows, the better. So she refrains from asking questions. And ultimately, she hopes Sophie will one day leave Dave entirely.

After all, she knows all too well what is like to be in a "loveless marriage".

The 60-year-old stayed with Sophie's father until her daughter left home. They were unhappy for more than a decade, she wrote. If she had her time again, she said, would have also looked for love elsewhere.

Though she's aware Sophie's infidelity is '"immoral", Sally is more concerned for the happiness of her daughter and grandchildren.

"If Dave were a better man, I'd possibly encourage her to work on the marriage. But thanks to Sophie's affair, I happen to think he's getting his just deserts," she said.

*All names are pseudonyms as real names were not provided.