The Sphinx (1916)

Unbekownst to each other, Charles Macklin and his widowed father Arthur are having an affair with an exotic dancer called The Sphinx. When both come to see her at the same time, Charles gets upset, denounces the Sphinx, and is knocked out by Arthur. Arthur then decides to marry the Sphinx, while Charles then resumes his affair with Frances, to whom he was engaged before he met the Sphinx.