One Ring to Bind Them

A puzzle wedding ring from the future washes up from the Rift and it's Ianto who puts it together... thereby creating a particular bond between him and Jack. Except that Ianto's got the only one, so the effect only goes one way. Will the other one turn up as well, or will they have to find a way undo the bond so things can get back to "normal?" (Will be a multi-chapter.)