Pointing out the obvious here but the wedding ring can have a lot of meanings, the couple gets to decide that, no one else.
Having said that, I brought up the wedding ring issue to my wife after we had gone through several discussions about all the other things and had time to think about them. We had noticed them in the "amateur" videos and that's why I brought it up to her.
I stated the obvious by noting it was a symbol of our bond but also noted things had changed in our relationship. I was nervous as I went on but continued, I said we would have never considered you being with a black man and asked about her wearing it when she was in bed with him.
She asked why and I said, for me your ring now symbolizes you are mine but can be with another lover anytime you please and it's my reminder. She was cool with the answer. My wife has changed a lot.