What Paul says by “way of concession” is that he wishes everyone to be as he is. The duties of spouses is an imperative. Biblical imperatives apply just as much to pastors as to laymen in the faith.
No, the immediate antecedent is returning to one's spouse after a temporary separation of bed, and this in contrast to his desire that everyone be as he is.
Biblical imperatives apply just as much to pastors as to laymen in the faith.
A concession is not an imperative. In any case, Paul is clearly giving his own counsel, not a Biblical commandment.