Symbolism in "Bluebeard" Variations

One symbolic element seen in the Bluebeard stories is the key. In the
Perrault version of the story, Bluebeard gives his wife the keys to the
storerooms containing all of his valuables. He uses the key to try and
 "unlock" the happiness of his wife, or at least, to keep the door to
happiness open and thus misdirect her. However, Bluebeard gives her the
specific instruction not to enter the little room at the end of the
hall, though he does give her the key. This small key is the key to
 unlock Bluebeard's anger, as well as the key that unlocks his past and
what became of his previous wives.  This little key also becomes the key
to her potential demise—because it is enchanted, she cannot wipe it of
 her misbehavior, and it is stained with the blood of the women in the room.

Similarly, in the Grimms' version ("Fitcher's bird"), the husband gives
the wife the keys to the estate and says that she can go anywhere except
 in one room with penalty of death. This small key represents the
husband's history. That it is locked away may mean that it is something
he wants private, but that he also wants her to find, otherwise he would
have removed the key to begin with. In the end of the story, it is a key
 (though not explicitly stated) that becomes the demise of the sorcerer
as he is locked in his house and destroyed by fire.

In the second Grimms' version ("The Robber Bridegroom"), there is no
mention of a key in this story, though the finger that the girl
 possessed is like a key as it is the element that unlocks the story of
the robber and is used to turn this robber over to the authorities so he
and his band of murderers cannot kill anyone else.

Another symbolic element present in the Bluebeard stories is the use of
 dreams and rings. Both the girl in "Fitcher's Bird" and Lady Mary in
"Mr. Fox" use dream telling as a means of confrontation. By using dream
telling, the protagonists can distance themselves from the action they
 witnessed, express to the antagonist their knowledge of his
transgressions, and find their way out of the marriage contract.

In both of these stories, as well, the protagonists witnessed the
antagonist's attempt to remove a ring from the finger of a murdered
 girl. The archetypal ring is associated with fidelity. The removal, or
attempted removal of the ring from the girl is symbolic, to the
antagonist, of the girls' fidelity, in death, to the antagonist.

Tatar, M. (1999). The Classic Fairy Tales. New York: W. W. Norton & Co.