Perhaps one of the most interesting aspects about the characters of Macbeth and Lady Macbeth is how their roles reverse by the end of the play.
At the start of the play, and through the murder of King Duncan, Lady Macbeth is the one who sees violence as the answer and it is she who comes up with the murder scheme, while her husband is racked with guilt and indecision, seeing and hearing things, his mind starting to snap. She mentally bullies him into taking action and after he kills the king and comes unglued ("Macbeth hath murdered sleep!"), she contemptuously tries to assuage Macbeth's feelings of remorse, telling him to essentially not think about it so much.
However, once Macbeth assumes power as king and starts to see the success his actions bring, he begins plotting murder (against Banquo's and Macduff's family) without consulting with Lady Macbeth at all, and by the final act of the play Lady Macbeth is the one who is walking in a daze, seeing visions, and racked with guilt.
Brand and Brittany,
As a starting point in comparing Lady Macbeth and Macbeth, look closely at Macbeth's soliloquy in Act I. vii. Macbeth thinks about the murder and begins to think about justice, morality, the good of Scotland, and the after-life. Macbeth is just about resolved to not murder Duncan when Lady Macbeth interrupts his decision.
Lady Macbeth recognizes Macbeth's hesitancy, so she plays upon his weaknesses. Macbeth, we learn, is not as self-confident as one may initially believe. He is a good man but impressionable. Lady Macbeth knows exactly what she wants and to get it.
Because of her gender and station in life, Lady Macbeth must live vicariously through her husband's success.
I hope this answer helps.