This is a great thread! It was threads like this on SI that led me down the path to discovering that I was likely dealing with a narc.
I think that knowledge is why I'm not still holding on to hope that he will "wake up" and do the right thing. It also knocked some reality into me and knocked me out of my own fog of sorts. I realized that for much of the last 10 years I was looking at him and our relationship through rose-colored glasses. I excused away everything (except the affair and his lack of remorse which was the first thing I couldn't excuse away). I held on to hope for the future without any indication in the present that he would ever be a better man.
Now that I know he never was the man he wanted me to believe he was and never will be, I'm out of excuses that I could make to myself about why I shouldn't let go.