In Macbeth, what is Lady Macbeth's complaint about her husband?

Lady Macbeth's first complaint about her husband is that his nature "is too full o' th' milk of human kindness" (1.5.17).  When she receives his letter, telling her about the Weird Sisters' predictions, she is concerned that Macbeth is simply too nice, too compassionate, to "catch the nearest way" to the throne (1.5.18).  She resolves immediately that he will be king, and she wants it right away, but if Macbeth is unwilling to kill Duncan,...

Lady Macbeth's first complaint about her husband is that his nature "is too full o' th' milk of human kindness" (1.5.17).  When she receives his letter, telling her about the Weird Sisters' predictions, she is concerned that Macbeth is simply too nice, too compassionate, to "catch the nearest way" to the throne (1.5.18).  She resolves immediately that he will be king, and she wants it right away, but if Macbeth is unwilling to kill Duncan, then it could take a lot longer.  This is unacceptable to her.

Once they've made a plan to kill the king, Macbeth does try to back out, and this provokes his wife to new levels of frustration with him.  Lady Macbeth asks him if he'd like to think of himself as a "coward" for the rest of his life (1.7.47).  She accuses him of being "green and pale" and insists that this is how she will consider his love going forward (1.7.41).  She says that he made her a promise, and his willingness to break it shows her just how little he loves her.  She argues that when Macbeth was willing to commit the murder, "then [he was] a man," implying that if he does not go through with it now, then he is less of a man (1.7.56).  She claims that she would sooner kill her own baby than break a promise to him. Thus, she accuses him of being cowardly and disloyal to her.