Is she required to fast three days after she swore an oath not to marry a religious man, then married a committed religious man?

You are required to expiate your oath, which involves feeding ten needy persons with food of the average kind you provide to your own family, or clothing them, or freeing a slave. If you are unable to do that, then you must fast for three days. You did well by breaking your oath and marrying a religious man, for the Prophet, peace and blessings be upon him, said: "Whoever takes an oath and then sees something better than it, let him do what is better and expiate his oath."