sounds like we are in similar positions concerning our W, apart from the fact I'm separated but seeing my W regularly. In my case, my W refers to the wall she has built as a moat that she can hide behind, and she will come out, dip her toe in the water, sometimes come across the moat but go back again. As you said, this is very frustrating and difficult to deal with - for all involved. My W has explained that I need to be patient, she has to see that the changes in me are for real and this is going to take time. Maybe your W is in the same sitch? Just some initial thoughts,
