The Alfred Hitchcock Hour (1962)

S1E14 The Tender Poisoner

Peter Harding, a corporate executive, is determined to revive the struggling career of his associate, Philip Bartel, by getting him into one of the company’s sought-after training programs. However, Peter soon learns that Bartel is contemplating leaving his wife, Beatrice, to be with his mistress. Concerned for Bartel's personal life, Harding resolves to intervene by stepping in and taking the mistress away from him, hoping to steer Bartel back onto a better path.