Thus he sought to kill both Banquo and his son Fleance in order to further decrease the chances of a later betrayal. His actions appear irrational on a surface level, but due to his avid focus on independence he would not seek counsel from Lady Macbeth, someone who is much more subtle and knowledgeable about internal politics and political intrigue. Macbeth's near irrational paranoia finally alienates him not only from his wife, but also the majority of nobles within the Scottish polity. Thus, while Macbeth's personal power continues to rise because he gains complete ownership over his own actions, at the same time he is also increasingly isolating himself from the outside world. With Macbeth's continuing disregard for Lady Macbeth, she finally succumbs to a combination of regret and guilt and ends her own life. In her final moments she continued to question, "what, will these hands never be clean?" (5.1.45). Macbeth in a similar fashion awaits his own prophesied execution at the hands of Banquo's heir. The ultimate result of his decision to isolate...

This is what ultimately led to the downfalls of both of these characters.
Macbeth's ultimate failure in his scheme to take the throne is his inability to maintain the strong bond of unity with Lady Macbeth. Both of these characters were able to accomplish their end of obtaining the throne because of their combined will. Lady Macbeth's ability to subtly use her wit and rhetoric was the catalyst behind the actions of Macbeth. When he lacked this guidance, he becomes strongly reliant upon his own brand of action, violence in order to solve his problems. The Macbeths' represented a model of teamwork as both sides needed each other's specific strengths in order to effectively accomplish their vision. When Macbeth disregards Lady Macbeth's influence, he ultimately created the collapse of their union and their success. The combination of these circumstances led to their mutual demise.