My wife’s first marriage was in a Protestant Church (she is protestant.) She divorced he first husband (he is Catholic.) She does not understand why we need an annulment if the Catholic Church. I explained to her that the Church does recognize the existence of a marriage between two baptised christians.
The Church recognizes the marriages of two Protestants and the marriages of two Catholics. It does not recognize the marriage of a Catholic who marries outside of the Catholic Church.
From what you have written, the marriage tribunal is going over your wife’s first marriage simply to verify the facts. Since her first husband was a Catholic and married outside of the Catholic Church, the marriage should be invalid.
Fr. Vincent Serpa, O.P.