In 1 Corinthians 7, the apostle Paul encourages believers with unbelieving spouses to stay together, saying “the unbelieving husband is made holy because of his wife, and the unbelieving wife is made holy because of her husband.” (v14). He goes on to say “For how do you know, wife, whether you will save your husband? Or how do you know, husband, whether you will save your wife?” (v16)
The apostle Peter encourages wives with unbelieving husbands to nevertheless treat their husbands with respect and love, saying “they may be won without a word by the conduct of their wives, when they see your respectful and pure conduct” (1 Peter 3:2).