The Inferior Sex (1920)

When his honeymoon is over, Knox Randall shifts his attention from his wife Ailsa to his business. Feeling neglected, Ailsa accepts her sister-in-law Clarissa's advice that a little jealousy might re-ignite her husband's interest. Undertaking a harmless flirtation with playboy Porter Maddox, Ailsa discovers that Clarissa has fallen madly in love with Maddox, who is using her to accumulate confidential information regarding Wall Street secrets. When Ailsa overhears Clarissa making plans to elope with Maddox, she hurries to save her sister-in-law.