Whose ambitions drive the play more, Macbeth's or his lady's? As ambition is the main theme of the novel, this turns out to be a very important question. Throughout the play, the figure of who is in control is frequently blurred, as Macbeth and his lady's ambitions trade places multiple times. This shows many distinctive traits about the couple.
At first look, you would think that the Macbeths have a quite rocky marriage, but upon closer inspection, you will realize that they actually have a good relationship, bound together by their mutual ambitions for power and influence. They seem to know that they have an equal standing in their relationship. Also neither of them hold the position of true authority in their marriage, as they trade positions frequently. .
Lady Macbeth obviously has control of Macbeth in the beginning of the play, encouraging Macbeth to kill Duncan. It is quite probable that Macbeth would not have killed the king if not for Lady Macbeth's persuasive words. She says to Macbeth in Act 2, Scene 2, "Had he not resembled / My father as he slept, I had done't- (Lines 16-17), truly encouraging him to carry out the murder of his King Duncan. Through this, it can be seen that contrary to the usual husband/wife relations of the times, Lady Macbeth will not settle to be seen as her husband's inferior. Her strong ambition to obtain more power is very important to the plot, and as was said before, Macbeth lacks the motivation to kill Duncan, although he is not lacking the notion of it. He had already thought about the murder after his meeting with the witches, and all that was left was to be compelled enough to do it.
Macbeth, the subordinate of the first acts, listens closely to his wife and slays his king. After the first massacre of the king and his servants, it becomes apparent that he has gained more confidence than he can truthfully handle. Soon after his promotion to king, he remembers his rule is in jeopardy as the witches told him that Banquo's offspring would inherit the throne.