Star Trek: Enterprise
Episode: ENT 008 - Breaking the Ice

Vulcan male and T'Pol's fiancee. Koss was an architect, and was betrothed to T'Pol during childhood. Before T'Pol was assigned to the Enterprise NX-01, she and Koss had met only four times. Because marrying Koss would have forced T'Pol to leave her post, she broke the engagement.