bbj, this is not a marriage issue and no amount of retreats or marriage counseling will help. Dan can not have a good relationship with anyone until Dan is good with Dan. If he had said he was looking for a retreat for himself instead of the marriage that might be reason to pause,
I am sorry to be blunt but these are the questions I have had to ask myself. This is my opinion of course, but marriage counseling would only serve a purpose after Dan works on Dan.
Me 54 DS19 and DS17 Married 06/1989 Divorced 01/2011