Father Grondin states that a marriage does not need to be consummated in order to be valid.
Exchange of consent establishes a valid marriage, between the baptized this is a sacrament. *Consummation *makes a valid, sacramental marriage indissoluable:
Can. 1057 §1. The consent of the parties, legitimately manifested between persons quali-fied by law, makes marriage; no human power is able to supply this consent.
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.
§2. After a marriage has been celebrated, if the spouses have lived together consummation is presumed until the contrary is proven.
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.
Doesn’t that contradict CCC paragraph 1652?
No. CCC1652 does not address validity of marriage or consummation.