MULDER'S RING

In the Season 5 episode, "Travelers," I noticed that Mulder is wearing a wedding ring, and the camera makes sure you are aware of it, and see it, but (and I have seen all eposides but the last three in the entire series) I don't recall mention of Mulder having a previous marriage, or ever referring to one in any of his conversations... Can you enlighten me on this? Thanks!
Rachel

Good catch. It wasn't Mulder's ring. David Duchovny decided to wear his real-life wedding room in that episode, but there was no story reason for it.