You need to provide more facts. Generally speaking direct sexual harassment involves one employee in a position of authority over another. The supervisory employee requests sexual favors in exchange for preferential treatment or threatens to terminate the employee unless he or she complies. If you were terminated because your dating relationship with your boss ended, then you may have a case.
The elements of "quid pro quo" sexual harassment are the respondent (can be a boss, supervisor, etc.) subjected the complainant to unwelcome sexual advances, requests for sexual favors or other verbal, visual or physical conduct of a sexual nature when: Submission to the conduct was made either explicitly or implicitly a term or condition of the complainant’s employment or provision of services; or submission to or rejection of the conduct by the complainant was used as the basis for employment decisions affecting the complainant.