It's difficult to say how common they are. In today's society, with so many distractions and opportunities for people to interact outside of their marriages, there may be more instances than in the past. But still, a large number of marriages are based on loyalty and commitment, so while it does occur, it might not be the norm. There are also cultural factors at play. In some cultures, any behavior that could lead to a husband feeling cuckolded is highly frowned upon and less likely to happen openly.
One story could be about a couple where the wife befriended a man at her work. Over time, she started spending more time with him than her husband. She would lie about where she was going and who she was with. Eventually, her husband found out she had been having an emotional affair which made him feel cuckolded as she was giving her attention and affection to someone else.
One reason could be lack of emotional connection. If the husband is not providing enough emotional support, the wife might be drawn to someone else. For example, if he is always dismissive of her feelings.
Such stories are not extremely common in mainstream literature. Mainstream literature often focuses on more positive and traditional relationship themes. However, in some niche or experimental works, this kind of complex relationship might be explored to show the breakdown of traditional family or relationship norms.
Sharing such stories often involves unethical and disrespectful content. We should focus on positive and healthy relationship stories, like a couple who overcomes difficulties together through mutual understanding and support.
In a story, the wife had always been adventurous and the husband was more of a homebody. The wife joined a club where she met a man who shared her interests. Slowly, she started to form a deeper connection with this man. She would lie to her husband about where she was going. When the husband finally found out about this relationship she had formed that was bordering on cuckolding, he was heartbroken. They then had to decide if they could salvage their marriage.
Well, it's not that common but it does happen. In some cases, it might be due to a breakdown in communication within a marriage. For example, if a husband is always busy at work and neglects his wife's emotional needs, she might form a closer bond with a friend which could potentially lead to such a situation. But overall, most people value loyalty in relationships and such occurrences are the exception rather than the rule.
This is an unethical and complex situation. But here's a fictional non - explicit story. There was a wife named Lily. She was in a marriage that had lost its spark. She met a man at her workplace who was very charming. She was reluctant at first but gradually got closer to him. Her husband, Mark, noticed the distance growing between them. Eventually, Lily realized her mistake and worked hard to fix her marriage.