There are many reasons that people find themselves in this type of situation. Sometimes neither was saved when they were married and then one later gets saved. Sometimes a companion backslides. Each situation is vastly different and has unique needs and difficulties.
To those that are living with an unsaved companion, it is important to remember your marriage vows and that these vows were not just to that companion but to God. That vow was “for better or for worse.” Usually when we get married, we don’t go into the vow thinking that it will turn for the worse. We have high expectations for our future with our chosen companion. But when the rug is pulled out from underneath you and all your expectations come crashing down, it is so vitally important that you have it settled that you are in this relationship for better or for worse. You need to drive that stake in, otherwise your decision making and how you deal with things won’t be stable.

 “Who shall abide in thy tabernacle? Who shall dwell in thy holy hill?…He that sweareth to his own hurt, and changeth not.” Psalms 15:1, 4

Sometimes the vows we make can turn to our own hurt. You must set your heart on the things of the LORD. Keep your promise and do all you can to see it through.

Don’t be discouraged or alarmed if it seems like disagreement is becoming the hallmark of your marriage.

 “Trust ye not in a friend, put ye not confidence in a guide: keep the doors of thy mouth from her that lieth in thy bosom.” Micah 7:5

Sometimes the one we once very closely shared things with, we are going to have to be careful with now. At times you are going to need a break and some release. It is very crucial who you choose to put your trust in as a confidant. You need people that are solid and have their heart and purpose set on God.

If you have an unsaved companion you can work with, do all you can to nurture that working. It is neither about winning arguments nor making points. Let the Lord do the arguing for you- leave it in His hands. That doesn’t mean that you are not going to feel bad at times nor does it mean you can never have something to say.

Try to make your spouse happy in whatever way you can. Sometimes that will be difficult. The unsaved are coming from a very different perspective and have different priorities. Many times they have an underlying root of bitterness there. They have a different thought, priority and vision for the family. It is important that your purpose is in more than just your family. Have a place in the body of Christ; Be productive and be faithful in what God would have you to do. That will carry you through a lot of difficult things. Don’t allow yourself to become lukewarm or you will be in a vulnerable place. If you keep your focus on serving God, your trials will become blessings that you can use to help others through difficulties.