That's what my spidey sense is saying. She wants to try for a new gig that would demand a move to DC or the like, and his identity is very tied to his life in Alaska. Some couples try to be bi-coastal for a few years; some just can't.
It is a fair supposition.
She always looked quite comfortable at the mike calling people out.
He more looked like he would rather be fishing.
After this many years of marriage, several kids and grandkids, they pretty much have been through the usual arguments, so why the divorce filing now?
Just speculating, but if she is indeed considering jumping back in, he might not be willing to go through the anal scoping they would surely be subjected to.