When my wife and I were married in the Catholic Church, I was a baptized Catholic and she was a non-practicing Jehovah’s Witness. At that time she was not baptized but she has since been baptized in the Catholic Church. Is our marriage a sacramental marriage?
Yes, your marriage is sacramental. There are two requirements for a marriage to be sacramental: (1) The marriage must be valid, and (2) both spouses must be baptized. A valid marriage may exist when one or both spouses are not baptized, but such a marriage is not sacramental. Prior to your wife’s baptism, your marriage was presumably valid but not sacramental because she was not baptized. Her baptism did not in any way invalidate your marriage so, upon her baptism: (1) Your marriage remained valid, and (2) you both were baptized. Both of the requirements for a sacramental marriage being met, your marriage became sacramental at your wife’s baptism.
The Code of Canon Law explains,
The matrimonial covenant, by which a man and a woman establish between themselves a partnership of the whole of life and which is ordered by its nature to the good of the spouses and the procreation and education of offspring, has been raised by Christ the Lord to the dignity of a sacrament between the baptized. For this reason, a valid matrimonial contract cannot exist between the baptized without it being by that fact a sacrament. (CIC 1055)