At the start, Kirito has a specific ring equipped, that you can't un-equip. If you know the story, you know which I mean, but for some reason, on floor 83, it's off, and I can't equip it? Was it something I said? to another girl?
Its your wedding ring I guess.. I think you are in the event where you got divorced with Asuna... To get it again you must finish the wedding ritual... Just do all the thing that showed in Kirito's memo...L+ R and then Square to bring the Memo's menu...Eventually you will get the ring back... --- One, Two Freddy's coming for you~Three, Four better lock your door~ Five, Six grab your crucifix~Seven, Eight gonna stay up late~Nine, Ten never sleep again~