1 Corinthians 6:18-20; 7:2

Flee immorality. Every other sin that a man commits is outside the body, but the immoral man sins against his own body. Or do you not know that your body is a temple of the Holy Spirit who is in you, whom you have from God, and that you are not your own? For you have been bought with a price: therefore glorify God in your body. 1 Corinthians 6:18-20

But because of immoralities, each man is to have his own wife, and each woman is to have her own husband. 1 Corinthians 7:2