STAY WHERE YOU ARE
Nevertheless, each one should retain the place in life
that the Lord assigned to him
and to which God has called him.
This is the rule I lay down in all the churches.
I Corinthians 7:17
Christians have freedom. Faith and the Christian life aren't restricted to any particular station or position in life. But they are above, in, and throughout all positions in life. Therefore, it's not necessary for you to accept or give up any position in life to receive salvation. Stay in whatever place the gospel finds you. You can remain there and be saved. It's not necessary for you to give up your marriage and run from your non-Christian spouse for the sake of faith or salvation. On the other hand, it's not necessary for you to become married for the sake of faith or salvation. If you are married, whether it be to a Christian or non-Christian, whether to a good or evil person, you are neither saved nor condemned because of that. If you are unmarried, you also are not saved or condemned because of being single. It's all free -- free!
As a result, if you are a Christian and remain one, you will be saved, and if you remain a non-Christian, you will be condemned. "This is the rule I lay down in all the churches" means "This is the rule I teach all Chritians to whom I preach. For I do not teach them to leave their positions in life and stir up unrest, but to remain where they are and live in peace." So you see that Paul doesn't call any position in life a blessesd one except this one: being a Christian. The others he frees up so that in and of themselves they neither save nor condemn us. But all positions in life -- no matter how well kept -- can be blessed through faith or cursed through lack of faith.