Article from: http://www.gotquestions.org/
Being married to an unbeliever can be one of the most difficult challenges in a Christian’s life. Marriage is a sacred covenant that joins two people together in one flesh (Matthew 19:5). It can be very difficult for a believer and an unbeliever to live in peaceful harmony (2 Corinthians 6:14-15). If one partner becomes a Christian after the marriage, the inherent struggles of living under two different authorities quickly become apparent.
Often Christians in this situation will look for a way out of the marriage, convinced that this is the only way to truly bring honor to God. His Word, however, says the contrary. It is very important not only to be content in our situation, but also to look for ways to bring glory to Him out of our challenging circumstances (1 Corinthians 7:17). The Bible specifically addresses those who are married to unbelievers in 1 Corinthians 7:12-14: “…If any brother has a wife who is not a believer and she is willing to live with him, he must not divorce her. 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. For the unbelieving husband has been sanctified through his wife, and the unbelieving wife has been sanctified through her believing husband…”
Christians married to unbelievers will need to pray for the power of the Holy Spirit to enable them to profess Christ and live in the light of God’s presence (1 John 1:7). They should seek God’s transforming power to change their hearts and produce the fruit of the Holy Spirit (Galatians 5:22-23). A Christian wife is obligated to have a submissive heart, even toward her unbelieving husband (1 Peter 3:1), and she will need to remain close to God and rely on His grace to enable her to do so.
Christians are not meant to live solitary lives; they need to find support from outside sources such as the church and Bible study groups. Being married to an unbeliever does not alter the sacredness of the relationship, so it should be the priority of every Christian to pray for his or her spouse and set a good example, allowing Christ’s light to shine brightly (Philippians 2:14). May the truth found in 1 Peter 3:1—that an unbelieving spouse is “won over”—be the hope and goal of every Christian who is married to an unbeliever.
Recommended Resources:Logos Bible Software and Surviving a Spiritual Mismatch in Marriage by Lee Strobel.