I found that living apart gave me the space I needed to "see" our relationship without being in the thick of it. We've been apart for 3 days shy of 6 months, and I am not going back to living in that hell. But while living in it, I rationalized what I did so I could survive the chaos.
Being outside now, wow, what a difference. He can live in his own denial - but keep me out of it. (Detaching is so much easier when you can go NC)