A - Thanks for the question. What we do know is that Jesus wasn't married. The question is hypothetical, but has some very interesting points that I would like to address.
The most historically accurate documents (starting with the Biblical writings and then more) tell us he was never married. The only documents that tell us he was married are later writings that are not historically accurate - they are later innovations and distortions of history. For instance the gnostic Gospels are non-Christian documents that invented many legends about Jesus. These have been made popular today with books such as The DaVinci Code.
In a real sense, we can say Christ was married to His Church, which the Bible describes as the Bride of Christ. In fact, Jesus himself said that:
Now John's disciples and the Pharisees were fasting. Some people came and asked Jesus, "How is it that John's disciples and the disciples of the Pharisees are fasting, but yours are not?"
Jesus answered, "How can the guests of the bridegroom fast while he is with them? They cannot, so long as they have him with them. But the time will come when the bridegroom will be taken from them, and on that day they will fast. – Matt 2:18-20
He then goes on to teach that celibacy is a great calling:
For some are eunuchs because they were born that way; others were made that way by men; and others have renounced marriage because of the kingdom of heaven. The one who can accept this should accept it. -Matthew 19:12
Christ wanted to show the radical love He had for us by giving Himself completely to us, His Church. Part of his plan of salvation included this radical sign of love for us in renouncing marriage for "the sake of the kingdom". This radical sign of love and sacrifice for his bride tells us what marriage is supposed to be all about, what his mission was, about his nature, and more.
Remember, human marriage is not eternal - till death do us part - but Christ's marriage to his Church is everlasting.
So, what would change about the faith?
1 - Our understanding of marriage, and sex.
2 - Our understanding of the goodness of celibacy and virginity.
3 - Our understanding of the mission of Christ.
4 - Our understanding of the purpose of the Church.
5 - Our understanding of the nature of heaven as "the marriage feast of the lamb".
So, in a sense, it would change our understanding about almost everything contained in the Catechism.