If you are a believer and you are already married to someone who is an unbeliever, God's Word tells you to stay married to your spouse (see 1 Cor. 7:12,13). If on the other hand, you are a single Christian who is considering getting married to an unbeliever, don't do it. God's Word says, "Do not be unequally yoked." (2 Cor. 6:14)
The most important relationship to a Christian of course is my relationship with Jesus Christ. Every other relationship is secondary. If a believer marries an unbeliever, he or she is choosing to ignore what God says about being unequally yoked. It is never smart to ignore God's Word, and that is certainly the case in a matter as foundational as marriage.
There is no spiritual unity between a believer and an unbeliever. Not an ounce of it. Why? Because a Christian has the Holy Spirit dwelling within him or her, whereas an unbeliever doesn't have the Spirit's indwelling presence. The new birth results in a new life and a new spirituality. There is no unity on that level unless both people are converted through faith in Christ.
Without spiritual unity, there can be no ultimate sexual unity. By "ultimate," I mean the type of sexual unity God designed a husband and wife to enjoy with one another. That only happens when both of them are in a relationship with God. Then and only then do they experience sex as God intended.
Sex between two unbelievers, or between a believer and an unbeliever, is not the way God designed it. A proper relationship with God is always more important than sexual intimacy. Without the first thing being in place, the sexual intimacy will not be the ultimate expression of God's design. And that approach will never bring the deepest level of satisfaction and contentment.
With a married couple that is unequally yoked, the unbeliever remains outside of God's grace and forgiveness. This does not prevent the believer from growing in the Lord as much as possible in that challenging situation. While their souls and their sexual relationship will not share any spiritual depth, the couple will nevertheless be loved by God. And hopefully the unbeliever will be won over by the witness of the Christian spouse and the working of the Holy Spirit.
While the purpose of getting married is never to "evangelize the lost," a believer who is already married to an unbeliever has the responsibility to try to reach the other for Christ. Hang in there and pray for your spouse's salvation. "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. 7:16)
It is preferable to never find yourself in that situation if at all possible. Granted, some people come to faith in Christ after getting married. They both were unbelievers when they were married, and then one of them gets saved. This actually happens quite often.
But when it comes to those who are not married, God has a clear message. As a Christian, do not unite yourself in marriage with someone who doesn't know the Lord and therefore doesn't love the truth of the Gospel. The two of you are on different spiritual trajectories. That is huge when to comes to having unity, or disunity in my marriage.
It is not wise for a Christian to even date an unbeliever. By allowing your heart to be given to an unbeliever, you risk placing yourself in a situation where it may be very difficult to walk away. So be careful Christian who gets your heart.
As a believer, do you really want to marry someone who will not be in a position to rely upon the love of God when you do things wrong and need forgiveness? That's not to say that every Christian couple always relies upon God's love to forgive one another, but at least in that situation it is available for those who are wise enough to receive it and share it with one another.
An unbeliever, on the other hand, does not have the wellspring of God's love on the inside. He or she has chosen through the continual and deliberate sin of unbelief to remain outside of God's grace, love and mercy. All an unbeliever has to draw on is "human love," and that is incredibly weak when compared to God's love. One is average. The other is supernatural.
Do you really just want to have an "average" marriage? Or would you rather have a marriage that soars higher and higher through the supernatural love and power of Almighty God?
Your marriage certainly won't be perfect no matter who you marry. Far from it. Both of you will be imperfect sinners. But there is an enormous difference between a marriage of two believers, and a marriage where such unity is nonexistent. So if you are still single, don't settle for someone who rejects the very Savior who shed His blood on the cross for your sins.
And if you are single and you long to be married, just remember who placed that desire in your heart in the first place. Look to your Creator and rely upon Him as you wait for that desire to be fulfilled in His perfect time.
If you have already gone ahead and married an unbeliever, can you still please God? Of course. Can you and your spouse enjoy any spiritual or sexual unity in Christ? Definitely not, at least not yet. Not until your spouse repents and believes the good news, which may or may not ever happen.
Are there many marriages where the couple is unequally yoked? Yes indeed. Does God love both of them? Yes. Do both of them love God? No. How could an unbeliever love God? We must first receive God's love in Christ before we can start to love God. We must first be converted in order to be brought into God's family. Then and only then does a person have a relationship with God, and the God-given ability to please the Lord. We cannot please God without faith. In fact, such a thing is impossible. (see Hebrews11:6)
You may find yourself today in a challenging situation as it relates to these issues. Pray to the Lord. Ask for wisdom. Turn to God's Word for direction. God's grace will see you through as you rely upon Him for strength and guidance.
Above all, know that you are loved by God. That is why He sent His only Son to die for your sins. Even though we have all made many poor decisions in life, our Lord is big enough to meet us where we are at and help us to love Him as we go forward in Christ.
Here is one final word to every married man who wants to do God's will: "Husbands, love your wives, just as Christ loved the church and gave Himself up for her." (Ephesians 5:25) Marriage requires sacrifice. Marriage requires perseverance. And marriage without Christ is not marriage as God designed it.