Is Lady Macbeth as guilty as Macbeth in the king’s dead?
Deciding who is guiltier is not easy in this case, but after reading and reflecting about the tragedy, some interesting points come out. Macbeth is a moral person and is aware of the consequences of his actions, he knows the World in a different way of his wife, he knows about wars, battles, what a man of courage and honor should be. Moreover, even being so aware of a moral life and knowing that a “Moral Taboo” cannot be break without bad consequences. Since the beginning when the “weird sisters” talk to him, he starts thinking about the idea of being king, and differently from Banquo – who also had heard the sisters’ prophecy and not giving importance to that – the thought of being King never let Macbeth’s mind, as we see below.
Glamis, and Thane of Cawdor! The greatest is behind.
Act 1, scene 3, lines 126,127
As well as the fight in his mind, between good and evil, even before writing to his wife.
I am Thane of Cawdor.
If good, why do I yield to that suggestion
Whose horrid image doth unfix my hair[...]
Act 1, scene 3, lines 147, 148, 149
My thought, whose muder yet is but fantastical,
Shakes so my single state of man that function
is smothered in surmise and nothing is
but what is not.
Act 1, scene 3, lines 153, 154, 155, 156
Lady Macbeth, instead is dazzled by the idea of being queen, and when read the news from her husband, she wants to be queen no matter if her husband have to kill a man, but without thinking deep about the consequences of that act. She starts evoking the evil spirits to help her free herself of women weakness, as we can see
Come, you spirits
That tend in mortal thoughts, unsex me here,
And fill me, from the crown to the toe, top-full
Of direst cruelty!
Act 1, scene 5, lines 44, 45, 46, 47.
It makes me think that both are guilty, because they had ambitious and evil thoughts since the beginning, even before they had met each other again after his meeting with the witches.
However, I tend to believe that Lady Macbeth is less guilty than his husband is, because she is not the one who really does it, she plays the devil voice in his husband hears, but he has the freewill to accept it or not. She is very hard when calls into question his manhood, but it is not excuse for a man kill another innocent and helpless man, who did not to him, but just the fact that is still alive.
When you durst do it, then you were a man,
And to be more than what you were, you would
Be so much more the man.
Act 1, scene 7, lines 55, 56, 57.

Certainly Macbeth gets worse and worse as the play goes on. He goes on murdering all kinds of people, or having them murdered, from Banquo on to Macduff’s family. Whereas, Lady Macbeth never commits any other murder. In fact, her husband stops including her in his murderous plans.