A mum-to-be's world has been shattered after uncovering a family betrayal of monumental scale, as she found out her husband had been having an affair with none other than her own mother.

The bombshell discovery revealed that the affair spanned 22 years, coinciding with the entirety of her marriage. To add to the shocking turn of events, it emerged that some of her siblings were in fact fathered by her spouse, reports the Daily Record.

In a heart-wrenching confession on Reddit, the woman, who is seven months pregnant, detailed her torment and the repercussions of the scandal, as reported by the Mirror. She also mentioned that her mother is now blaming her for "ruining her life" after exposing the affair.

Providing context, the woman explained: "I'm 40. My parents - my dad, 63, and mum, 60 - have been married for 43 years. I have six siblings. I've been with my husband, 39, since we were 15.

"I fell pregnant at 17 and we moved in with my parents. I gave birth to my now 22 year old daughter. We got married at 18 shortly after. My dad's father passed shortly after our wedding and left his ranch-style house to my father. My grandparents built a house next door to my parents when they retired."

She went on: "My parents decided to let us live in this house and told us this would be my inheritance. My husband and I had no issues with this. We went on to have a 20-year-old, 14-year-old, and five-year-old, and I'm currently seven months pregnant with my last child, a boy, due in April."

After describing their close-knit family and seemingly perfect home life, she then reveals the shocking discovery of her husband's affair with her mother. She writes: "I thought I had a good marriage, we were intimate more than twice a week, we went on date nights, we bought each other gifts, we didn't fight.

"My entire world was shattered on New Year's Eve when I returned early from a girl's trip I had taken with some friends. I walked into my bedroom to find my mum having sex with my husband. My mother screamed at me to get out of 'their' bedroom, which really shook me up even more."

When she confronted her husband, she discovered that his sexual relationship with her mother wasn't a one-time occurrence, but had been ongoing for many years, even before their marriage. "I asked him for the truth. He told me that my mum seduced him when we were 18 and living in their house. They'd been having unprotected sex at least once a month for longer than we were married," she added.

"I ran the math and was horrified because the timeline meant my twin brothers and youngest brother could be my husband's."

Revealing her mother's infidelity to her father, she said: "I made my husband confess and my dad was devastated, he and my mum were high school sweethearts too. Needless to say, we could hear my mother screaming from her house when he confronted her."

Amidst the chaos that followed, she detailed the step-by-step account of revealing the affair at a family party hosted by her sister. "At the party, I had my 22 F daughter take all the kids to our basement and put on a movie, leaving only the adult children and siblings and I told them exactly what they'd been doing," she articulated.

She continued, stating: "Most of the family is on my side, except my 3 youngest siblings, 38 F sister, Ex's entire family. They all say I'm an AH for dropping this publicly."

The fallout from her actions included her mother losing her position as a children's pastor after the affair came to light, as described by the woman: "My mum has since been let go as the children's pastor there and she claims I've essentially ruined her reputation and life."

She also laid bare the aftermath impacting her personal life, highlighting her impending divorce and falling out with her mother. She expressed: "I'm now over a month removed, still extremely bitter and angry at my mother, especially at her hypocrisy of calling me a w**** and shaming my family, when she's done much worse."

"I also have an intense hatred for my ex now, as he was having an affair with both my mum and me, sometimes even coming to our bed just minutes later. He got my mother pregnant less than a week after getting me pregnant, and while I initially thought it was lovely that I shared a pregnancy experience with my mum, she was actually carrying my children's half-siblings. He has completely shattered my trust in men and their ability to be faithful."

Reddit users have rallied around the original poster, with one person responding: "Good on you for not literally stabbing your husband. I wouldn't be as strong."

Another added: "You need to change this title from 'I ruined my mum's life and reputation' to: 'My mum destroyed our family, and at the same time ruined her own life and reputation'. You did absolutely nothing wrong, and you are a victim, just as much as everyone else in your family who was hurt by this.."

A third shared: "'My mum ruined her life'. There I fixed it for you."