So got into coffee house discussion with an Anglican friend, is sex necessary for marriage to be valid? He was bouncing around in a few different areas of this question. For instance, if a dramatic accident occurs before consummation and the couple cannot consummate their marriage is the marriage valid? In short, I said “yes the marriage is still valid.” He had trouble believing that Joseph and Mary never had sex. Can an impotent couple (both man and woman) get married? Is this valid?
Well, you’re both a little bit right.
Can. 1061 §1. A valid marriage between the baptized is called ratum tantum if it has not been consummated; it is called ratum et consummatum if the spouses have performed between themselves in a human fashion a conjugal act which is suitable in itself for the procreation of offspring, to which marriage is ordered by its nature and by which the spouses become one flesh.
Can. 1141 A marriage that is ratum et consummatum can be dissolved by no human power and by no cause, except death.
Can. 1142 For a just cause, the Roman Pontiff can dissolve a non-consummated marriage between baptized persons or between a baptized party and a non-baptized party at the request of both parties or of one of them, even if the other party is unwilling.
When a couple exchanges their consent of marriage truly and freely, a valid marriage exists. However, it is not an indissoluble marriage. It may be dissolved by the Holy Father but only for a just cause. The indissolubility of a valid marriage comes about through its consummation.
This is quite different from an annulment. An annulment states that there never was a valid marriage. A non-consummated marriage is still a valid marriage, it is actually a valid bond that is dissolved by the authority of the Church at the request of one or both parties for a just reason.
As for impotence, canon law states:
Can. 1084 §1. Antecedent and perpetual impotence to have intercourse, whether on the part of the man or the woman, whether absolute or relative, nullifies marriage by its very nature.
Note that the impotence must be antecedent, meaning that it was before the exchange of vows. In the example you provide, the impotence comes about after the exchange of vows. Therefore the marriage, in your example, would remain valid but not indissoluble.