A practising Catholic will be marrying a non-practicing Catholic (who may not believe in God anymore) in the Catholic Church. Can they have a Nuptial Mass with the non-practicing Catholic not receiving Communion? Since sacraments should be received in a state of grace, and the non-practicing one obviously is not in such a state, what does it mean for the non-practicing one to receive the sacrament in that state? Will the non-practicing Catholic still receive the grace of Matrimony?
This question is one of the several reasons why the Catholic Church stipulates an extended period of time for marriage preparation, typically one year before the wedding day. The first step for the couple to take is not to shop for banquet halls or churches or exotic locations, but to sit down with their pastor so he can assess their needs.
Among many other things, like maturity of the couple, their ability to give consent, their freedom to marry, if there have been previous marriages, or there are any serious impediments, pastors are to assist the Christian party or parties to make an effort to improve their faith practices, as it is beneficial to the success of their marriage and future family.
If both parties are Catholic, and if one or both parties either refuse or does not show adequate effort to be more serious with their faith, pastors are to deny them the celebration of the nuptial mass on the wedding day, but instead offer to have the wedding liturgy without mass instead. It is necessary since it would be sacrilegious to knowingly offer Communion to a non-practising Catholic, or a sign of contradiction to have a wedding mass but only offer communion to one of the newlyweds.