The Legionaries of Christ, an influential Roman Catholic religious order, have been shaken by new revelations that their founder, who died a year ago, had an affair with a woman and fathered a daughter just as he and his thriving conservative order were winning the acclaim of Pope John Paul II. Before his death, the founder, the Rev. Marcial Maciel Degollado, had been forced to leave public ministry by Pope Benedict XVI because of accusations from more than a dozen men who said he had sexually abused them when they were students. Now the order’s general director, the Rev. Álvaro Corcuera, is quietly visiting its religious communities and seminaries in the United States and informing members that their founder led a double life.