Orange County Assemblyman Tom Umberg on Thursday admitted to and apologized for cheating on his wife in a four-year affair that ended about the time of his election in November. Umberg went public with his indiscretion after his former mistress, who possesses e-mails they had exchanged, threatened to ruin his political career, said George Urch, Umberg's spokesman. In a brief written statement Thursday, Umberg said he has apologized to his family and will regret forever the mistakes and pain that he has caused his wife of 23 years, Robin, and their three children. "I love my wife very much and...