How has being king and queen affected both Macbeth and Lady Macbeth changed?
Lady Macbeth becomes increasingly riddled with guilt. She very quickly disappears from the action of the play and does not return until the first part of Act V, when it is apparent that she has totally lost her mind. She ruminates and sleepwalks, mumbling incoherently and within earshot of her servants and the doctor who is called in to treat her. She states things like, "Out damn spot," in reference to the blood that has stained her hands (after the murder of Duncan) and her soul. She cannot bear the guilt and suffers a complete breakdown. Macbeth, on the other hand, becomes a cold-blooded, calculating killer. He orchestrates the murder of Banquo without even asking for or needing Lady Macbeth's help; he must retain his crown and knows that Banquo's sons are prophecied to become kings. After that, he slays Macduff's family and promises that he won't spare anyone who threatens his crown. Fleance remains in his mind as someone he must deal with at some point (after he escapes the attact against him and his father, who did not survive). In short, Macbeth goes on a killing spree; Lady Macbeth, after a brief yet important banquet scene in which she talks Macbeth out of the hallucinations he is having (he too goes through a period of guilt) basically fades away into mental illness.