The only right and Godly thing to do (if he is indeed having marital issues) is to step aside. This however does not mean that he has sinned, or faltered from his beliefs.
I personally know a few pastors who have gone through this. They will either have a close friend (or family member) step in an pastor the church while the issue is resolved, or completely resign.
1 Timothy 3:1-5
This is a true saying, If a man desire the office of a bishop... A bishop then must be blameless, the husband of one wife, One that ruleth well his own house...For if a man know not how to rule his own house, how shall he take care of the church of God?
Taking the time to focus on your personal life is the Godly thing to do. This will keep you blameless before God AND the World.
PERSONAL OPINION:
I have always been taught the following order; God, Family, Church.
1) Be sure your own salvation is good
2) Be sure your family is safe and in line
3) Then take care of the church.
I have seen to many men of God neglect their family over pursuit of "Political Power" or to much time spent "working" for the church.