I don't question what the apostles wrote by the inspiration of the Holy Spirit. As for Paul not being married it is well understood that he was a member of the Sanhedrin who have a requirement that they be married and at least 30 years old. As for their commendation of not being married, they do not say that is for leadership. Paul does specifically spell out requirements for leadership.
As to why he made those requirements I'll simply let him speak.
1 Timothy 3:5 For if a man know not how to rule his own house, how shall he take care of the church of God?