The Cyrano Game by Linda Rue Quinn

He stalked his prey for months before he came up with a plan, sitting in a darkened theater while Sarah and Matthew, her new husband, watched the play Cyrano de Bergerac. Of course! He would force the undeserving Matthew to tell him everything about Sarah while discrediting him in her eyes. Intensive planning and building took all of his spare time, but she was worth it, and soon she would come to him.