Welcome to the boards.
I am in a similar situation (although my interest is 400 miles away). My overall suggestion would be to start slow. Date your new guy. As for physical, again take it slow, find out what your hubby would be comfortable with, start with just kissing or "first bast" and go from there. As he gets more used to the idea that just because you are emotionally and physically involved with another man, doesn't mean that he is getting any less of you, but perhaps even more.
Life is about the journey and not the destination,
so what better way to know life
than to wander all the roads and paths set before you.