Do you notice anything different with his eyes? Does he seem to try to act happy? My D's call it 'fake daddy happy'. It's like he's wearing a mask. The strain and stress of the sitch is very evident in my H's face.
Not talking to his son and family sounds like guilt and depression to me. They seem to have a tendency to cut themselves off and withdraw from family and friends. It seems like if they do this they can go on like we don't exist. Makes it easier to carry on with the fantasy.
