If you came to faith after marrying, or if your spouse has simply never shared your convictions, you're not facing a situation the Bible is silent about. Paul addressed it directly, to real believers in a real church, and his counsel deserves to be read in full rather than reduced to a single verse.
Stay, if your spouse is willing
Paul's first instruction may surprise people who assume Scripture would counsel immediate separation: if an unbelieving spouse is willing to remain in the marriage, the believer should not leave. The marriage retains real spiritual significance, and Paul explicitly does not treat it as a lost cause.
Called to peace, not control
If an unbelieving spouse chooses to leave, Paul says plainly that the believer is not enslaved in that circumstance — God has called us to peace, not to a lifetime of striving to force a relationship to continue against another person's will. This matters, because it means faithfulness never requires manufacturing an outcome only God can bring about.
Your presence matters more than you may realize
Paul also raises a possibility easy to miss: the believing spouse's presence may itself carry sanctifying significance within the marriage and the home, in ways impossible to fully see from the inside. This isn't a guarantee of a particular outcome. It is a real, biblical reason for hope that a faithful presence is never wasted, even when it feels invisible.
Where this goes next
You are not responsible for producing your spouse's faith. You are responsible for your own faithfulness — and Scripture treats that faithfulness as something with real weight, whether or not you ever see its full effect.