But to the rest say I, not the Lord (τοις δε λοιποις λεγω εγω, ουχ ο Κυριος). Paul has no word about marriage from Jesus beyond the problem of divorce. This is no disclaimer of inspiration. He simply means that here he is not quoting a command of Jesus.

An unbelieving wife (γυναικα απιστον). This is a new problem, the result of work among the Gentiles, that did not arise in the time of Jesus. The form απιστον is the same as the masculine because a compound adjective. Paul has to deal with mixed marriages as missionaries do today in heathen lands. The rest (ο λοιπο) for Gentiles (Ephesians 2:3) we have already had in 1. Thessalonians 4:13; 1. Thessalonians 5:6 which see. The Christian husband married his wife when he himself was an unbeliever. The word απιστος sometimes means unfaithful (Luke 12:46), but not here (cf. John 20:27).

She is content (συνευδοκε). Late compound verb to be pleased together with, agree together. In the papyri.

Let him not leave her (μη αφιετω αυτην). Perhaps here and in verses 1. Corinthians 7:11; 1. Corinthians 7:13 αφιημ should be translated "put away" like απολυω in Mark 10:1. Some understand αφιημ as separation from bed and board, not divorce.