Both are Promethean, as shown by their consequential struggle for power, yet in a Promethean relationship, as stated by Arthur Paul Patterson's enticing article, Passions of Prometheus, there is always a dominant being in the bond.Thus, Macbeth can now be seen as the dominant being in the relationship, and since Promethean's Lady Macbeth is a controversial figure.
They see her in her commitment to evil and in her realisation that the acquisition of the Crown has not brought her the happiness she had expected, and finally, as one who breaks down under the strain.
Lady Macbeth has to clean up what he has done wrong and has to return the daggers herself. Here, Shakespeare defines both Lady Macbeth and Macbeth's strong and weak characters.
Lady Macbeth being the strong one yet as a duo, he... In my opinion, the answer to this cruelty shown by Macbeth is his "mutual greatness" promised to Lady Macbeth.
Whether she was bluffing, the imagery that Macbeth would have had in his mind at this point would have been frightening. Macbeth is so awed by this woman who is his wife, who has so much power that he cannot believe it.
At this point in the play, Shakespeare re-confirms just how close the relationship between Macbeth and Lady Macbeth is and that she has the power and he listens to whatever she has to say.