The Honeymoon's Over - S3.E9

When Lester's cousin and his wife come to visit the Jenkins, Mary brags about how they are the perfect couple who never argue and still begave like Honeymooners after five years of marriage. When they arrive, Sherry reveals to Mary that Ed is stiffling her and is too overprotective and she says that she is going to leave him that night.

Once Ed finds out that she left, he becomes depressed and there is nothing that the Jenkins or residents of 227 can do to cheer him up. Sherry decides to come back and Mary coaches Ed on what to say, and tells him that he should change; he should be less overprotective. Sherry takes him back (or rather they take each other back).