After Indy the first time, she went to Nepal. To be fair, she went with her father, but the cold suited her, and the isolation. When he died, she couldn't think of a reason to go back to the States; "home" was just a word for an empty house on a cold dark lake, with doilies and venetian blinds that had to be dusted. Nepal was easier, even with the burden of keeping the bar going and the never-ending yak-butter tea. If she raged at Indy about burning down the bar, she realized later that it was just what she needed to start moving again.
After Indy the second time, she couldn't go back to Nepal, that was going backward, and Marion never went backwards. (Indy didn't count.) England wasn't exactly going forwards, but Ox was there, and Colin, and--most importantly--Indy wasn't. England was always too tame for him, too many people and no room to breathe. But Marion liked the people: they pulled her out of herself, out of her anger, gave her something other than Mutt to care about, especially once the war started. And Colin was, well. He was everything Indy wasn't: courteous, kind, noble. She loved him, and not only for Mutt's sake.
After Colin, after the war, she found herself back in the States anyway. Still not going backwards, though: she'd never lived in Ohio before. And the weather was better than in England, although after eight years in England she was appalled by what passed for tea in America. Mutt grew fast, and she was busy, with Mutt and Ox's help, building a life in a new place for the third time. She planted corn and tomatoes in the yard, her hands filthy in the rich soil, and Mutt came home from a school trip with a pocket full of arrowheads.
And then, after all of that, there was Indy again, at which point she had to admit that maybe she'd done no more than move in one great circle. Maybe a spiral, every loop gathering someone else into her orbit: Mutt, Colin, Ox.
That was something she could handle. And if she could keep coming back to Indiana Jones after thirty years, maybe a bit of repetition was good for her. Every time she came around, the world only got bigger.