The phrase "unfaithful spouse" refers to a husband or wife who is not loyal or honest in their marriage. It suggests that the person is being disloyal by having romantic or sexual relationships with someone other than their spouse. Full definition
The partners of unfaithful spouses almost always experience the trauma of discovering the betrayal, and are often re-traumatized by their partners, pastors, or misguided couples therapists by being told to «quickly forgive and forget» and «not talk about it anymore». (counselingatl.com)