There is a difference between willingly choosing to marry someone who is unsaved, and two people who are both unsaved getting married, and then one getting saved. That is the situation in 1 Cor. 7.
"[FONT="]To the rest I say this (I, not the Lord): If any brother has a wife who is not a believer and she is willing to live with him, he must not divorce her.[/FONT][FONT="] [/FONT][FONT="]13 And if a woman has a husband who is not a believer and he is willing to live with her, she must not divorce him.[/FONT][FONT="] [/FONT][FONT="]14 For the unbelieving husband has been sanctified through his wife, and the unbelieving wife has been sanctified through her believing husband. Otherwise your children would be unclean, but as it is, they are holy.[/FONT][FONT="]15 But if the unbeliever leaves, let it be so. The brother or the sister is not bound in such circumstances; God has called us to live in peace. 16 How do you know, wife, whether you will save your husband? Or, how do you know, husband, whether you will save your wife?" 1 Cor. 7:12-16
I have a friend who was not saved, and married her atheist husband. She got saved a few years later, and has the gift of evangelism. She leads people to the Lord almost every day. But, so far, not her husband. So, my friend has committed to be the most loving and kindest wife possible. That is her witness to her husband. I personally have been praying for him for over 13 years. I have talked with him repeatedly about Christ. My husband has talked to him about how Jesus changed his life.
This man has some major issues in his life, from when he was in an accident with a bunch of other teens in a pickup truck which crashed, and he was the only one who survived, with some major injuries. God knows his hurts! At any rate, they do have a wonderful marriage. One that is almost to be envied, except for the pain my friend has, knowing that her husband's eternal destiny is not with God.
Which is to say, anyone contemplating marriage needs to marry someone in the faith, to avoid the issues which can crop up when a believer is married to an unbeliver. My friend is lucky, he felt it was ok that she raise the children as Christians, including going to Bible school, upon graduating from high school. But not all unbelievers are like that! Because, marriage is also about children!
And if you are married to an unbeliever, well, I guess prayer and a solid witness is the only way to go. Please pray for Robbie, my friend's husband, that God will break down the barriers around his heart, and save him![/FONT]