The Marriage Sacrament is shared between two people and can be added during the registration process or later via the member card. If there is both a “Head of Household” and a “Spouse” in the family, the Sacrament record will be added to both members. You will receive a notification like this:
Then you will see the participants of the Sacrament as such when you view the Sacrament Details.
For information about adding a Sacrament see this article.