Hey Bilbo, I see that often too - it seems like complete denial. They want it all and even make plans for the future. Maybe this open marriage just might work out - sheesh.
My W was still talking about future plans, family trips, and things she want to do to the house, and I am thinking (why would we even discuss this because this passes up all of the other steps that need to happen).
Once the discussion was opened up, that all changed. I did tell her that I wanted her to leave and that I would not live like this any more. Now - I don't think things have really changed between us, but she knows that I am serious and sticking to it. I have shown her this by not acting like her bff any more and she knows why without saying anything and showing that I am moving forward with my future.
She tries to suck me back into that same old bff role (this would be all well and good if it was real and part of true h/w roles - and searching for this is my weakness.)
Not saying any of that is relevant in your situation, just what's happening in mine (and it does seem similar)
My intention is to not move out, but it may come to that.
Me-45 W-44 S21, S18, D15 T-27, M-21 BD Jan 2014 PA revealed March 2014 In-house separation - April 2015 I filed - Aug 2015 She moved out Oct 2015