During Shrouded Manor, it can be found in the basement vault of Shroud Manor in the kitchen room on a small table next to Candy's holotape, however if you pick it up without reading Trevisani's terminal entries you won't be able to drop it.
Xbox One If the ring is picked up before reading the entry on Trevisani's terminal that adds "Find the wedding ring" to the player's miscellaneous quests, it will be impossible to remove, since the quest's completion requires picking up the ring, which can't be dropped.
If you pick up the ring after killing Candy but before activating the workshop and completing Shrouded Manor, the game allows you to store the ring in a container as it is not quest-flagged yet. Once you have read Trevisani's terminal entry, you will then recieve the miscellaneous quest and can then retrieve the ring from wherever you left it to complete it.
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