Co-teaching is like an arranged marriage!

As I do my observations of the co-teaching classrooms, you can tell there is a disconnect between the teachers.  I have conferenced with the teams, gave feedback and suggestions, and suggested peer observations.  The teachers are supposed to plan together, but that is not happening either.  I have gone back to some of these same classrooms, and there is no change.  How do I get teachers to change their mindset?  Is there some good literature out there that compares marriage and co-teaching?  I truly believe a lot of the resistance is due to the teachers not being held accountable.  This is so frustrating and the students are getting the short end of the stick!