There are some similarities and some major differences between family and marriage counseling.
When we are working with a family, the emphasis is on how the family system works and is arranged. Sort of like looking at the solar system. By focusing on the entire family, no one person is singled out as the "sick one." Treatment is done by nudging the family into different ways of behavior.
Marriages are viewed as a "two planet" system, if you will, each revolving around the other. Again, we don't focus on who the "bad guy" is, but on how to understand the difficult behavior, and how to learn to change it.