Hi Gabriel
I was going by Matthew 19:9 where Jesus Gives a exception on; fornication=porneia=sexual Immorality.
Mt. 19:9
**I say to you, 7 whoever divorces his wife (unless the marriage is unlawful) and marries another commits adultery." **
10
[His] disciples said to him, “If that is the case of a man with his wife, it is better not to marry.”
11
He answered, “Not all can accept [this] word, 8 but only those to whom that is granted.
12
**Some are incapable of marriage because they were born so; some, because they were made so by others; some, because they have renounced marriage 9 for the sake of the kingdom of heaven. Whoever can accept this ought to accept it.” **
Verse 9 deals with what the Catholic church calls “invalid” or unlawful in the eyes of God. What protestants take this to mean is Law of the land to justify a divorce which those who followed Moses law of divorce comes deals with the flesh. Now this unlawful marriage from the bible has a huge theological Hebrew aspect which Jesus reveals in verse 11 “Not all can accept this word”. In the law deals with the flesh, while Jesus reveals these mysteries in marriage are “only those to whom that is granted” when He shifts the topic to the heavenly gift of “celibacy” if one is called not to marry by God.
Jesus introduces the validity of celibacy in answer to the Pharisees comment in verse 10 “It that is the case of a man with his wife, it is better not to marry”
What we are dealing with here are two different covenants of marriage, the old covenant law allowed divorce to which Jesus was explaining “unless the marriage was unlawful” which pertains to Jews getting married to pagans as incestuous (cf. Lev 18). According to the rabbinicial tradition also included impedements which meant that those who converted and who were already married was not that the marriage could ever be dissolved, but that the marriage never took place. The “unlawful” is also transcribed to “unchastity” which connotes these dealings of marriage under the old covenant law.
You see the Catholic position is very biblical and ancient. What Jesus does to marriage in the new covenant is raised to a sacrament and placed matrimony where God originally created it for, to procreate in Love in the image of God between man and woman “only”.
The Catholic church cannot ever dissolve a marriage, like protestants allow divorce. The Catholic church takes the biblical position as recognizing a marriage as valid or invalid. She can never dissolve a marriage, but can only annul a marriage that is unlawful in the eyes of God, which defines that a marriage never took place.
Another point I would like to make here, is that “adultery” is never a reason given to annul a marriage. A separation can be granted, but the two wedded are never free to remarry, less they committ adultery as Jesus teaches.
In summary, because marriage mirrors the eternal union between Jesus and his bride the Catholic Church. God would never divorce his Bride (church) on the reason of adultery, because God Loves unconditionally. Thus the Catholic Church will not or allow divorce in the body of Jesus Christ for a reason of adultery, only if the marriage was unlawful in eyes of God.
Now we get to the point what is a lawful marriage and what is an unlawful marriage in the new covenant established by Jesus Christ himself. A lawful marriage in the Catholic Church can never divorce, an unlawful marriage is never takes place and is annuled in the Catholic Church. You just need to be correctly informed was your marriage lawful or unlawful in eyes of God, not in the eyes of old covenant or the law of the land.
I will yeild here, because I am not sure if these topics is what you are wanting to discuss.