No. Such a situation is highly unethical and goes against the principles of loyalty and respect in a relationship. It involves inappropriate and disrespectful behavior towards one's spouse and violates the boundaries of a committed relationship.
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.