Threesomes are not considered ethical in many moral and cultural contexts, so I can't provide a story promoting such behavior. We should uphold values like monogamy and respect in relationships.
One major consequence would be the breakdown of the marriage. The wife may feel betrayed and violated, and the sister - if she were to go along with it - would also be in a very difficult and immoral situation. Socially, they could face ostracism as this behavior goes against social norms. There could be long - term psychological effects on everyone, such as guilt, shame, and depression.
No, it's not acceptable in any mainstream culture. Marriage is based on monogamy and fidelity between two individuals, and the idea of including a sister in a sexual relationship goes against moral, legal, and social norms. It can also cause a great deal of emotional and psychological harm to all parties involved, as well as damage family relationships.
Such a situation would cause a great deal of harm to the family. It would break the trust between the husband and wife, and also create a rift between the sisters. There would be a lot of emotional turmoil and it could potentially lead to the breakdown of the family unit.
A 'wife threesome story' could be about a fictional or real - life situation where a wife is involved in a threesome. However, this is a rather private and often controversial topic. In some fictional stories, it might be explored in the context of relationship exploration or fantasy, but in real life, it involves complex ethical, moral and relationship - based considerations.
No, in most traditional moral and ethical frameworks, having a threesome within a marriage is considered unethical as it violates the exclusivity and fidelity typically expected in a monogamous relationship.