This would create a huge rift in the relationship. The wife may experience a range of negative emotions such as anger, sadness, and disbelief. The friendship involved would also be ruined. It could also have an impact on the family and friends network around the couple, as this sort of behavior is not acceptable in society. The person who did this would have a very difficult time rebuilding any form of positive relationship with their spouse or others.
There is no evidence to suggest that such activities occur in a gym environment. Gyms have rules and ethics in place to maintain a proper and respectful atmosphere for all members. This kind of description violates the basic norms of a public fitness place.
In such stories, you might find themes of taboo exploration and the challenge of societal norms. But keep in mind that the content can be highly provocative and not everyone's cup of tea.