S9·E15 Pat's Secret

Robert discovers Pat smoking and she pleads for him not to tell anyone. When Amy later smells smoke on Robert, she tells everyone that he has been smoking. When Pat doesn't tell the truth, Robert ends up being yelled at. The next day, he tells Ray and Debra the truth, but it doesn't take long for the two to blurt out the secret in front of everyone, which leads to many more secrets being revealed.