This topic definitely hits a nerve with me. My XW had an EA (she says no PA but I guess I can never be sure) and married the OM 5 weeks after D was final. I do believe my inability to completely open up and be vulnerable contributed to my XW looking somewhere else. I was too scared of being hurt so I would close myself off and protest that "We shouldn't need each other." It was a self fulfilling prophecy.
As soon as she dropped the bomb and I finally understood much she was hurting, I realized how screwed up I was in my thinking. If I was to save my M or have a successful new R I had to be completely open and make myself vulnerable. Michele's solution based principles really spoke to me. I'm not sure of what FOO issues caused this but reading DR reinforced for me that I didn't need to know. That didn't have anything to do with the solution.
Unfortunately, I didn't save my M but I am in a new R (fearles) and have made a conscious effort to be vulnerable. I did begin to do this with XW but it was too late as she was in love with OM. Her words to me. I have had to force myself at times to open up and be honest with my feelings. Having success makes it easier. When a SO does not ridicule, tell you you shouldn't feel that way, and honestly appreciates the steps you are taking it makes it easier to stay open. Of course I had to overcome my fears and assumptions that I knew what her replies would be. Just having that first positive experience can reinforce R patterns. I couldn't imagine having this kind of intimacy with another woman. I have said and done things I could never do in previous R's and I realize how much I was missing. I would never want to jeopardize that.
I am the man who is loving my kids and will keep them from continuing this cycle of destruction.