Tammy Wynette’s daughters agreed Thursday to drop charges against the late country star’s manager-husband, whom they named as a defendant in a lawsuit alleging drug addiction caused Wynette’s death last year. But the lawsuit will continue against Wynette’s private physician, whom the daughters accuse of malpractice in treating Wynette with large amounts of narcotics. “My six-month nightmare has ended,” said George Richey, Wynette’s husband when she died on April 6, 1998, at the age of 55. Four weeks ago, Richey agreed to have the singer’s body exhumed. Autopsy results are pending.