I Married a Woman (1958) on Netflix

Marshall Briggs, of the Sutton Advertising Agency, is hard-pressed to come up with an idea to follow his successful "Miss Luxenberg" beauty contest for the Luxenberg Beer company. His original contest popularized Luxenberg Beer and led to his marriage to the winner, Janice Blake. Pushed by his boss, Frederick W. Sutton, to come up with a new idea, Marshall has neglected his wife, and his mother-in-law is suggesting to her daughter that her husband is running around on her. Meanwhile, Janice learns that she is pregnant. Marshall decides that since Janice is no longer "Miss Luxenberg" but "Mrs. Luxenberg" a great idea would be to round up all the former winners, who have married, and have a "Mrs. Luxenberg" contest. Running the idea up the old flagpole (per 1950s Madison Avenue advertising custom) reveals that the last winner is pregnant and most of the former winners have gotten fat drinking Luxenberg Beer. But the contest has already been launched. Marshall's gray-flannel suit is in need of dry-cleaning.