Well, today I am facing that fear. My wife is taking our daughter down to her parents for a while and I plan on using some of that time to 'just be'. I don't know if I know how to clear my head of thought, but I am going to try. I think that the greatest lessons in life are the ones taught to us when we aren't paying attention. Introspection or 'soul searching' have always played a key role in informing me about my PTSD and how it impacts my life.
I think a good portion of the emotional detachment that my wife experiences from me is attributable to not being able to get my mind to shut up long enough for my day to day life to register in a meaningful way. I plan on talking to my wife about making time once a week for me to focus my mind. Before I was in the military I had the uncanny ability to focus on a single problem or idea and explore it meaningfully from all angles. It made me VERY good at chemistry and drafting. Maybe I just need to find something that will appeal to my affinity for spatial relations. Building models. Wow. Where did that thought come from. Time to search online for local hobby shops. I think that's what I am going to do to focus my mind and clear it of all the other junk. Time to build a model.