Yes, definitely you're bored....This is possibly as simple as weight gain or loss on wife or husband's part and the other partner switched hands to be companionable, or even as a kind of sweet joke: "Hey, if you're wearing yours on the right we'll be right-handers together" or whatever.
It could just be that one of them is left-handed and got tired of having the ring "in the way" on the dominant hand. I don't like rings on my right hand because I'm right-handed and rings seem awkward and heavier on that hand. If the convention were to wear wedding bands on the right hand, I'd probably move mine to the left.
My mom never wore her wedding band. She worked in a business where many employees were not permitted to wear any rings or watches at work, ever, for safety reasons, so she didn't either, though she was office staff and not covered by that requirement officially. She was relieved to have an excuse not to wear a ring on her tiny, arthritic fingers! No one ever questioned if she was married. And I often don't have my wedding and engagement rings on because I take them off to clean house or when I have skin issues and sometimes they stay off for a few days or a week. I'm no less married, and nobody asks about them.
The left "ring" finger for the wedding band is purely a cultural convention and as you've noted, in other cultures they might wear the band on another finger. And there are people in this culture and others who wear no rings at all but are no less married than any married person who chooses to wear a ring. I note that there was a post saying that people should follow the "norm" so that others wouldn't speculate about them. I wouldn't care what others thought, and if they want to speculate about my marital status based on jewelry -- time for everyone to get a hobby.