I don't see the comparison to the military as valid either because military are not deployed for years.
And what planet do you live on?
Of course military personnel can be stationed away from their home base for years at a time. Even in peacetime, US soldiers could do a year in Germany, followed by a year in Korea, followed by a year someplace else. Not to mention the fact that peace can turn to war in an instant, and regardless of the length of deployment, the military parent might never come home.