I'm certain this applies to half an unsaved, married couple getting saved and not to a Christian who marries in violation of the "Be not unequally yoked..." command.  Nothing is said about the MARRIAGE being sanctified, just the husband or wife.  You can't read more into it than is there.

regardless, it IS a valid marriage in Gods eyes or we would not be called to remain in it

That is an opinion that is not supported by Scripture.  To marry outside of God's will (and we've all been taught that God has a plan for our lives) is being just as disobedient as doing anything else outside of God's will.  As far as non-believers are concerned what makes you think that, when a person has no relationship with God, getting civilly married all of a sudden gives the non-believer a relationship with God?

sure its supported in scripture.
A marriage to an UNbeliever is CLEARLY prohibited in 1 cor. 7....to take an UNbeliever as ones spouse.
But Pauls not tell the believer to LEAVE the unbelieving spouse if they are pleased, but to stay with them.

this case clearly shows that it is NOT Gods will that we marry an UNbeliever, but once married we ARE indeed married to them...barring being tricked into marriage or something similar as with Jacob and Leah...

The Lord told Hosea (Hosea 3:1), "Go, show your love to your wife again, though she is loved by another and is an adulteress. Love her as the Lord loves the Israelites, though they turn to other gods and love the sacred raisin cakes." We therefore, have to be faithful to our covenant with our spouse, even when there is unfaithfulness and hurt; and bring healing to our spouse by our prayers, sacrifices and support.

Bethrotal was the firsr part of marriage, and was completed a few months later when the husband took the wife into his house.

Betrothal was fully binding and lawful marriage.
When Joe was about to put Mary away, he was divorcing a wife.

http://www.jewishencyclopedia.com/view.jsp?artid=995&letter=B&search=betrothal


.

The divorce God hates is divorce in a marriage He has ordained.  Not all marriages are of God.  Simply because a couple decide to marry, run to the altar and invoke the name of God does not mean that marriage is of God.

The reason the divorce rate is as high in the Christian community as it is in the world is because so many Christians do not bother to ask GOD who they should marry (if He wants them to marry at all) but simply ask God to bless THEIR choice. 

In the United States the religious marriage ceremony has been replaced in many (if not most) cases by the State civil ceremony where the couple, the witnesses and the pastor performing the ceremony are required to sign a State marriage license and the churches have generally bought into the idea the a couple is not married unless they have had a State civil ceremony.  There is no Biblical support for making a marriage a State affair.

while I agree with your concept of asking God whom we should marry...my life being a testimony to this fact....that does not alter that once married, even to an unbeliever, we ARE indeed 'married' to them before God.
1 cor 7 is proof of that fact..

    Divorce is absolutely prohibited by the Gospels (Mk 10:11-12, Luke 6:18; Matthew 5: 31-32). In Matthew’s gospel the exception is for unlawful marriages.  The exception in the Greek text is porneia (which means incest or fornication), and not moiceia (which means adultery). The exception is for marriages between close relatives, which according to Mosaic Law (Lv 18:6-18) were unlawful, because, they were considered as incest. According to some authors it also refers to Jewish betrothal process, in which, prior to the marriage, if it was discovered that the bride was not a virgin (had committed fornication), the groom could back out. Such was the case when Joseph had planned to back out, when he found out that Mary was pregnant with Jesus.

Porneia...aka ‘’fornication’’

http://www.geocities.com/divorceandremarriage/11.html

Porneia is not limited to any particular sexual act.
It is sexual sin in general committed by anyone, with anyone( including animals) married or not.

Sex was created for a man and his wife...outside of that it is fornication...porneia....whoredom

Marriage covenant is a covenant of love.  Since God is love (1 John4:, it is a covenant of God.  No one therefore, can put aside the covenant (Matt 19:6). Divorce therefore, goes directly against God; and those who remarry after divorce commit adultery (Luke 16:18). God is therefore, not pleased with the offering of those who divorce their spouse (Malachi 2: 13-14).

  God always stays faithful to His covenant with us. When we were unfaithful to Him, He brought us healing by sacrificing His own life.  As believers, we are called to love our spouse just as Christ loves us (Eph 5:25).  The Lord told Hosea (Hosea 3:1), "Go, show your love to your wife again, though she is loved by another and is an adulteress. Love her as the Lord loves the Israelites, though they turn to other gods and love the sacred raisin cakes." We therefore, have to be faithful to our covenant with our spouse, even when there is unfaithfulness and hurt; and bring healing to our spouse by our prayers, sacrifices and support.

    Divorce is absolutely prohibited by the Gospels (Mk 10:11-12, Luke 6:18; Matthew 5: 31-32). In Matthew’s gospel the exception is for unlawful marriages.  The exception in the Greek text is porneia (which means incest or fornication), and not moiceia (which means adultery). The exception is for marriages between close relatives, which according to Mosaic Law (Lv 18:6-18) were unlawful, because, they were considered as incest. According to some authors it also refers to Jewish betrothal process, in which, prior to the marriage, if it was discovered that the bride was not a virgin (had committed fornication), the groom could back out. Such was the case when Joseph had planned to back out, when he found out that Mary was pregnant with Jesus.

There are many differnt views by those who are against divorce about this 'fornication' issue.

Can you explain to us why the rest of these 6 are errant ?

 The divorce/remarriage issue is one of the most argued topics today among christians. Among the remarkably varied beliefs there are a great many variances even within a given doctrine. An example would be the ''fornication'' (greek "porneia" (strongs g4202) issue.

      Here are a few of the differing ideas on what ''porneia/fornication'' is believed to be by those of the anti-remarriage camp(S)....

    1) Some of the anti-remarriage doctrines teach that this ONLY applies to Jews, even today, and that divorce was never permitted among the gentiles.
    2) Some state the same, that it was for the Jews alone, but now has evolved into a matter of unlawful PREmarital sex for all people, Jew or gentile.
    3) Other believe it only applies to a person who is either divorced and remarried themselves or married to a divorced person, that they are in ''fornication'' by Jesus' words and putting away is permitted under these conditions.
   4) Another group actually claims that ''fornication'' is ONLY incestuous marriages for which Jesus is giving permission to divorce. But that would mean that in Acts 15 that the Jerusalem council was ONLY prohibiting sex with ones blood relatives and omitting the multitude of other sexual sins possible (bestiality, prostitution, etc).
   5) One of the newest additions to the list of ''fornicators'' is one I just found where ''fornication'' is said to be ''miscegenation", or the interbreeding of races (so now I guess God is sending folks to hell if one parent was Jewish and the other spanish (/sarcasm)
   6) Even others admit that ''fornication'' in Matthew 5 an 19 is adultery, as we believe, but that Jesus isnt permitting remarriage under ANY circumstances.