This is the dividing point of the letter to the Corinthians. Now the remaining chapters are answers to questions by the Corinthians.

1 Corinthians 7 - vs.1 - “concerning the things you wrote unto me.” It is good that a man and woman stay single. For the single person attends to the Lord without distractions. Married people have to attend to their spouse and children, as well as the Lord. Vs.2 “Nevertheless, to avoid fornication, let every man have his own wife, and let every woman have her own husband. 3 Let the husband render unto the wife due benevolence: and likewise also the wife unto the husband.”

If a believer has an unsaved mate, let them live together, for the unsaved mate is sanctified and the children are made holy before the Lord. Vs.13 “And the woman which hath an husband that believeth not, and if he be pleased to dwell with her, let her not leave him.
14 For the unbelieving husband is sanctified by the wife, and the unbelieving wife is sanctified by the husband: else were your children unclean; but now are they holy.”
Marriage is sacred to God. It was the first institution He established with Adam and Eve.