I (like Janie) left a 25 year relationship. Well the last 10 were more separation in the same house. And even with that length of time of no emotional connection it still hurt terribly when I said "enough." I hurt for him and for the us we used to be.
I managed to get happy again, but then it is not my nature to be unhappy, which is probably why I stuck to it so long. It would have been better for everyone, kids included if I had left 10 or more years earlier.
Hindsight is a wonderful thing, ain't it? Totally fekking useless.