The only thing I can suggest to you is this when your W says she has to "let go of herself" that SHE needs to make a concious effort to do that.
Our C suggested to my H that in order to concentrate on "US" at home that he needed to literally, mentally put everything he deals with on a shelf at the guard shack on his way out of the hangar when he's heading home. Otherwise he comes home and has this tick-sheet constantly going through his head and there is no room for me.
Eventually, once your W becomes accustomed to conciously putting things aside to make room for you two....she will be able to do it without having to concentrate on it. But bear with her, it will take time for her to learn to do this.
Has your W been to a Psychologist by any chance who does concentrate on Bio-Feedback? If not, that might be an idea....they can concentrate on showing her ways of relaxing, techniques that really do help her let stress go from her body/mind....and they can do it in such a way that she can see it on graphs etc as they monitor her.
My H went to a Bio-Feedback specialist at first....who didn't do much talking and I thought the money was wasted...but if nothing else he did teach my H how to shift his way of thinking....so he has the tools, my H just has to practice using them. So that coupled with a really great MC seems to be finally paying off.