I'm not entirely sure what 'beat' means here precisely. If it means 'defeat' in some sense, perhaps it could be stories where a man's actions or circumstances led to his wife leaving him because he was constantly being defeated in life, like losing jobs repeatedly or being unable to achieve goals, which put a strain on the marriage.
There was a man who lost a bet with his wife. The bet was on who could save more money in a month. He thought he had it in the bag, but he ended up spending more on impulse buys. As a result, he had to take his wife on a romantic weekend getaway. It was an unexpected outcome for him, but it brought them closer together as they had a wonderful time on the trip.
Well, perhaps a man lost a bet to his wife about who could grow the nicest plant. He was so sure he could do it better with his 'dp' (which could stand for a special plant food or something). But in the end, he lost. As a result, he had to clean the garage which was full of old tools and junk. His wife supervised with a big smile on her face.
I don't think they are common. In today's world, we have laws and social norms that protect the rights of individuals, especially women. Betting on a person like that is not acceptable. However, in some old folktales or extreme historical cases, you might come across such stories.
I know a story where a wife bet that she could finish reading a very thick novel in a week. But she couldn't. So she had to sing a love song in front of all their friends at a party. It was really cute.
Well, in general, any form of sexual coercion or non - consensual situation is unethical. When it comes to so - called 'lost bet sex stories', if there is any lack of true consent from one or both parties, it's wrong. In a healthy relationship, sex should be based on mutual love, respect and free will.
The following are some recommended novels about lost wives: The Strongest Husband, Reboot 90, Return to the Day Before My Wife's Death, Pick Up a Fox Fairy as My Wife, Super Young Master Tyrant, My Wife Can Buy, My Wife Is Too Tsundere, Young Master Gu: Getting Back His Ex-Wife and Having a Baby, and Years After Divorce.
Another story might be in the context of a competitive sport (the 'beat'). A man was so obsessed with winning races or championships that he didn't have time for his family. His wife got tired of always coming second to his athletic pursuits. She left him to find a more balanced and fulfilling relationship. This shows how an extreme focus on one area (the 'beat' of competition) can cost someone their most important relationships.