The following lines reinforce the concept that Macbeth does not want to notify his wife about Banquo's murder until after it has occurred: "Be ignorant of the truth, dearest Chuck,/until thou cheer the deed," says A. "It's best if you don't know about this until you see the outcomes," the lines imply.
The fact that Macbeth doesn't feel the need to tell his wife about Banquo's death right away shows that he is not interested in sharing his success with her.
Applaud the deed till then. Macbeth clearly does not want his wife to be complicit in the murder of Banquo and his son. Macbeth appears to be shielding her from the horrific visions related with Banquo's and his son's death. This time, he wants her acquitted of the deaths of Banquo and his son.
Macbeth does not tell his wife that he is killing Fleance and Banquo since she is already crumbling under the weight of Duncan's murder's shameful secret. He will not disclose the details of the crime with her for her sake. Instead, he tells her that they had a visitor from Glamis who told him he would be next if he did not take action.
This implies that Macbeth is aware that she is not really happy with his decision to kill King Duncan and become king himself. He just wants to save their family name from further dishonor.
However, what Macbeth doesn't realize is that even though Lady Macbeth isn't happy with his decision, she still loves him very much and will do anything to protect his reputation. This is shown through her actions after he becomes king. Even though she knows he is responsible for murdering King Duncan, she still believes he can change and keeps this secret from everyone except Forrester. She even goes as far as helping him escape Scotland after he has been crowned king!
So in conclusion, Macbeth does not tell his wife everything about his plans because he does not want to burden her with his problems. He also does not tell her everything about what happened at Glamis since it would only make her unhappy.
Macbeth informs his wife that he has prepared "a frightful act" for Banquo and Fleance and urges her to be cheerful and courteous to Banquo at the evening's feast in order to lull Banquo into a false feeling of security (3.2.45).
Banquo Macbeth does not inform his wife that he is killing Fleance and Banquo since she is already crumbling under the weight of Duncan's murder's shameful secret.
Why does Macbeth seem to ask Banquo so many seemingly innocuous inquiries regarding where he is riding? To assess his behavior and learn about his goals, as well as Fleance's, to set the murder plot in motion. Banquo replies to all of Macbeth's questions, which shows him to be a worthy opponent.
Banquo has already warned Macbeth that they will meet in battle, so Macbeth wants to know more about Banquo and his forces. He also wants to know if Banquo has any children, since he himself is without descendants. Finally, Macbeth asks if Banquo has received letters from King Duncan, since he has not. As we know from later events, when Macbeth orders that these letters be delivered to him before he dies, they will prove crucial to his fate.
It is interesting to note that Macbeth never asks Banquo how he feels about being prophesied to become king. Perhaps this is because they have already established a strong bond of friendship through their discussions about future wars and rulerships, or perhaps Macbeth just assumes that Banquo will agree with his plans to kill King Duncan and take his place.
This is the current response. When Macbeth informs his wife, "We will move no farther in this transaction," she blames him first for suddenly breaking a pledge, which she figuratively equates to a drunken hope. She also questions his bravery and appeals to his honor. But ultimately she agrees to go along with his decision.
Lady Macbeth's reaction to Macbeth's news reflects both her guilt over her part in their crime and her fear of what will happen to them if they are discovered by King Duncan or others. Her words, "We will proceed no further in this business," indicate that she does not want to engage in any more acts related to their plot but at the same time knows there is nothing to keep them from continuing if they so desire. Even though she fears discovery, she does not try to talk Macbeth out of going through with their plan.
They have been married for ten years and has one son. Although they love each other deeply, their marriage has been plagued by violence and murder. Together, they have committed three murders to secure the throne. Now that the crown has been won, they cannot go on as before. Something needs to be done about their bloody deeds or else they will be caught and executed.
It is important to note that although Lady Macbeth has some role in plotting the murders, she does not feel guilty about her part in them.
Macbeth is concerned that Banquo's "royalty of nature" may pose a challenge to him, which is one of the reasons he orders the murder of his erstwhile closest friend. Macbeth is furious that he has wrecked his own peace in order to become king, and that all he has done would result in Banquo's offspring becoming rulers. He feels guilty about this, and so decides to kill off everyone who could prove his guilt.
In the scene quoted above, Macbeth tells himself that he is acting from noble motives by killing King Duncan in order to be king himself. However, this isn't true, as he knows very well that he is just trying to secure his own future by murdering the king. Macbeth is also aware that Malcolm, the new king, will not tolerate his crime, but he doesn't care - he wants to get away with it.
It can be said that Macbeth is angry at Banquo because he believes he is a threat to his reign, but this isn't entirely true either. What Macbeth really needs to do is ask himself if he is a good man, before going ahead with his plans. If he isn't, then he should admit his guilt and seek forgiveness before God and humanity.
Banquo didn't cause any harm to Macbeth, nor did he have any part in ruining his life.