Maybe she said, "Yes...but...you have to do this, this and this first". Or something like that. So she's wearing it on her right hand until the conditions are met?
Good point. If their arguments are real (and I have my doubts, but who knows, I don't live with them), that would be a good way to do it. Somehow I doubt that after 27/28 years of living together that she suddenly got sick of his behavior in the last 2-3 years. I'm not saying it isn't possible. She did have the kids to distract her before. Now they are both moved out or in college, she only has Gene to deal with. It would be plausible that you would focus more on the relationship at that point and start questioning it.