The Gottman's are THE people in MC. Attachment theory is good too! The main thing with their method is that the marriage is what is treated. You aren't dwelling on the past, but learning skills to move forward, bond, make memories, and working a bit on communicating.
I really urge you to check their site out, and see them in action on youtube!
Formerly Workinprogress H :55 M :over 29 yrs. Together : 33 D : college D : adult BD and left : May 2013 Separated Experimenting/Replay
