About that pesky wedding ring on Mulder's finger in "Travelers"?

Frankly, I'll be surprised if this hasn't come up in conversation here before, but I searched and searched and could find neither forum topic nor answers question about it, so here I am, asking.

Throughout "Travelers," episode 15 of season 5 which takes place in 1990 wherein Mulder learns the origins of the X-Files, his father's involvement in McCarthy conspiracies, and other such things, Mulder is wearing a gold wedding band on his left hand. This is most notably seen at the end, when Mulder holds his face in his hand (see below) but can also seen at the beginning, in link.

Being a first time serious watcher (when it originally aired, I used to just watch it when it was on, so I decided to go through the seasons on Netflix in order), I was intensely curious, and thought SOMEONE on the Internet would have an answer about this, but I have exhausted my googling skills. Does anyone here have any plausible theories as to what that ring was about?