A man finds out something surprising about his fiancee

Rob was standing on my doorstep, ashen and trembling. He still couldn't speak even as he sipped at a mug of tea after my flatmate and I had ushered him into our front room. Gradually, his powers of speech returned and the story emerged. Something had happened, but that something was terrible to Rob himself, not Karen.

Now, you have to understand that Rob and Karen were the most balanced, wholesome couple I knew. They had recently gotten a new flat together, each returning to their respective flats for a couple of weeks while it was being painted. That Friday, she had left her keys at his flat by accident. He was passing by her place later that night, so he stopped off and rang the doorbell.

No answer. So he let himself in to leave the keys, with a note, on the kitchen table for her flat-mate to return to her. Only, the house wasn't empty - he heard some movement in the front room. In an instant, he blundered in on Karen - the woman he was due to marry - having sex. With her flat-mate. With another woman.

Three weeks passed. Rob had called off the wedding - obviously - and was trying to put his life back together. One morning, he got a call from Karen, asking if they could meet up to settle any disputes over money and belongings. He agreed.

Predictably, when they met, an argument began. "I don't know why you think it's so strange!" she screamed. 

And it began to spill out: that she had made contact with lots of people. There are parties and pubs that are value-free. So now there are meeting grounds for de facto support groups for people engaged in homosexuality. And what they want is to normalise what we have long considered to be profoundly abnormal.

- 1971, from The Guardian

Isn't this disgusting? How could anyone have ever been so close minded and judgmental? Clearly, she was in the closet.

Well, I just lied. It's from 2002, and this is the actual excerpt:

Rob was standing on my doorstep, ashen and trembling. He still couldn't speak even as he sipped at a mug of tea after my flatmate and I had ushered him into our front room. [...] Gradually, his powers of speech returned and the story emerged. Something had happened, but that something was terrible to Rob himself, not Karen.

Now, you have to understand that Rob and Karen were the most balanced, wholesome couple I knew. They had recently moved out of their flat while it was being redecorated, each returning to their respective family homes for a couple of weeks. That Friday, she had left her keys at his place by accident. He was passing by her parents' place later that night, so he stopped off and rang the doorbell.

No answer. So he let himself in to leave the keys, with a note, on the kitchen table for her mum and dad to return to her. Only, the house wasn't empty - he heard some movement in the front room. In an instant, he blundered in on Karen - the woman he was due to marry - having sex. With her dad.

Not her stepfather. Not her adopted father. Her actual, biological dad. She was 22 years old. There was clearly no coercion taking place.

Three weeks passed. Rob had called off the wedding - obviously - and was trying to put his life back together. One morning, he got a call from Karen, asking if they could meet up to divide their mutual belongings, the accumulation of over three years' cohabitation. He agreed.

Predictably, when they met, an argument began. "I don't know why you think it's so odd!" she screamed. "I know lots of people who do this." That stopped Rob in his tracks. "Who?"

And it began to spill out: that she had made contact with lots of people over the internet (and consequently in person) [...]. The internet is value-free: it doesn't care or know whether you are selling a secondhand car or buying arms. [...] So now there are chatrooms and websites that are de facto support groups for people engaged in incest. And what they want is to normalise what we have long considered to be profoundly abnormal.

It's very common for people in non-GSA consanguineous relationships with immediate family to view it as emotionally distinct from a normal romantic or sexual relationship, and thus to not consider it cheating. This is especially the case when they're involved with a parental figure. I don't agree, and they should at least understand that those not involved will see it as cheating regardless, but that has no bearing on his specific reaction to this specific case. He seems far more concerned that it was her father than the fact that she was having sex with another man without his consent.