I have only 30 seconds to reply but here's my first thought...it IS unnatural to be living the rest of your life with a partner other than your XH. But it is just as unnatural to be living the rest of your life with no partner at all. What's unnatural is your XH out of the picture. That is a huge loss. But that can't be avoided. Now you're trying to figure out the best path forward knowing it will never be what you originally hoped for either way. No shame in rebuilding a new life in place of the old.
Me:38 XW:38 T:11 years M:8 years Kids: S14, D11, D7 BD/Move out day: 6/17/14, D final Dec 15