In the beginning of the play, Lady Macbeth is very much the driving force in the marriage. Macbeth tells her about the prophecies, and she tells him that he needs to kill Duncan. He is reluctant, and she pushes him on. Lady Macbeth is annoyed. Why did he even bother to tell her about the witches if he wasn’t going to do anything about it?
What beast was't then
That made you break this enterprise to me?
When you durst do it, then you were a man;(55)
And, to be more than what you were, you would
Be so much more the man. (Act I, Scene 7)
Lady Macbeth plans everything carefully, and makes sure Macbeth carries out her orders to the letter. She gets annoyed with him for feeling fear and doubt, and she scolds him for being a coward. Gradually, he begins to gain confidence. When Malcolm and Donalbain flee and he sees that the plan has worked, the tables turn. Now he begins to take control of the relationship. Fearing that she has created a monster, and Macbeth is no longer following her lead, she asks him what he is planning.
Be innocent of the knowledge, dearest chuck,(50)
Till thou applaud the deed. (Act 3, Scene 2)
He shuts her out, and she no longer knows what is going on inside his head. His plans become more erratic, and more murderous. He has Banquo killed, and Macduff’s entire family. Soon he has become trapped, holed up in his castle with whoever is still loyal to him, while Malcolm’s army comes. At this point, Lady Macbeth can no longer bear the guilt she had in causing this. She kills herself.