That's what's been happening with me, FG. The feelings eventually start to follow the reality of the sitch. She has no romantic feelings for me despite my best efforts to remake myself, she makes it clear over and over, time after time, and, eventually, there was enough of that accumulated that even I started to see it for what it is (i.e., nothing worth having).
I was at first pretty much in abject, white-hot agony most of my waking moments. As the inhome sitch has progressed and become "the norm", and I've seen the behavior and heard what's been said, etc., I've slowly moved to where I can't even see any longer how or why I'd be with this woman absent a whole host of changes she in no way thinks she needs to make, other than because it *might* be better for the children. Given that the two of us can't really manage to go more than 2-3 weeks, tops, without a fight one or both kids witness or overhear, I got to the point where even the stay together/stay unhappy model makes no real sense. You guys seem more consistently cordial, though, so you may have reason to wrestle more fitfully with the "do I keep doing this, even though it makes me miserable" question.
Me: 46 W: 44 Married: 17 Together 21 D13; S10 BD: 03.03.15 (Not attracted to you) Almost 2 years trying, alone, to save marriage Status now: Divorced (effective 06.13.17)