1 Corinthians 7:12-14

For the rest of you who are in mixed marriages—Christian married to non-Christian—we have no explicit command from the Master. So this is what you must do. If you are a man with a wife who is not a believer but who still wants to live with you, hold on to her. If you are a woman with a husband who is not a believer but he wants to live with you, hold on to him. The unbelieving husband shares to an extent in the holiness of his wife, and the unbelieving wife is likewise touched by the holiness of her husband. Otherwise, your children would be left out; as it is, they also are included in the spiritual purposes of God.