It sounds like a good plan that you are moving upstairs and telling others etc. I think it gives more of a healthy separation to the situation. It is difficult, and it does take a while to get through that early phase of hoping your WAS will 'wake up' and recommit.
One thing to think about perhaps is consistency. So, you refuse to share a bed whilst your W remains involved with someone else..fully support that. You now need to try and get that 'distance' into the R overall with your W. That does mean not trying to hold hands etc. It probably means not even going for the walk for now!!
Anyway, good for you to be taking steps and don't look over your shoulder at what your W might be thinking. Do this for you. Set yourself a lovely space up there in the attic, get yourself settled and enjoy the chance to have a bit of 'you' time.
Best of luck with things :-)
T 13 M 7 Me 48 H 46 SS 15 BD 7.14 PA D final 5.16 (H filed)
We receive & we lose, and must try to achieve gratitude & embrace with whole hearts whatever of life that remains after the losses - Dubus