He must know and love Christ.
This is the most essential criterion for a husband. There is nothing unclear about God’s will here.
God’s will is clear: Believers must marry only other believers.
We are meant to be a separate people, special and holy to God. This does not mean that we cannot be friends with unbelievers (as the Bible explains elsewhere) but it does mean that we cannot enter into a marriage relationship with them. The Bible does talk about special cases in which one of the spouses becomes a believer after marriage and remains married to an unbelieving spouse, but that is not the same as a believer deliberately agreeing to marry a nonbeliever.
The Christian woman who knowingly marries a nonbelieving husband runs the high risk of having her heart tempted away from the Lord. In fact, she has already been tempted away from the Lord because she allowed her heart to be claimed by a man that the Lord specifically told her not to marry. Having made that choice once, she is more vulnerable to making that choice again. Her love for her husband has already led her away from the Lord, to the point where her faith is secondary to her romantic relationship…
This concept goes even deeper. Eric and Leslie Ludy, authors of numerous books about relationships, have a love story that proves the importance of God’s central role in the relationship. Eric and Leslie knew that their relationship was right when Leslie’s father explained that he knew the relationship was of God because Leslie had grown closer to God through her relationship with Eric.
If a man is not actively drawing you toward God, then he is actively drawing you away from God. If you compromise on this issue, you will compromise on other issues. A non-Christian man is not worth it, no matter how “different” he may seem. The only truly different man is the man who is willing to live, suffer, and even die for Christ. If you choose a man with a “halfway faith,” what does your choice says about your faith?
My parents’ wedding rings are braided, made of three strands of gold intertwined with each other. Why? A braid symbolizes the nature of their marriage, for marriage does not involve just two people. It involves three people: the man, the woman, and the Lord. This illustrates the Biblical proverb: A threefold cord is not quickly broken.
No relationship in Christianity is about just two people. It is about what God creates between two people out of their unity in Him. He is the common ground. Never accept less than a man who belongs first and foremost to the Lord, and only secondly to you. Your relationship cannot be about you both, as if the relationship is an end in itself. First and foremost, your relationship must be about the Lord. As Jesus said, Whoever loses his life for my sake will find it. 
Love Christ more than you love each other and you will love each other more.
 2 Corinthians 6:14-17
 Ecclesiastes 4:12
 Luke 9:24
None of my life has gone the way it was "supposed to go," but I don't love my life any less because of the hardships and new directions. I see so much unexpected good in it, and I want others to see the good in theirs.