I am going to approach my wife tonight. I am going to express that I agree with her, our Marriage is beyond repair.
Are you sure you understood the coach to say that you should tell your W that the M is beyond repair and to mislead her to think all you want is to be her friend, knowing full well that in a week or two you would "try again" (whatever that means to you)?
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!