Initially, Lady Macbeth thinks of her husband as ambitious but ultimately "too full o' th' milk of human kindness" to do anything disloyal or untoward in order to achieve his potential, as outlined by the Weird Sisters (1.5.17).  She believes him to be incapable of ruthlessness and also easy for her to manipulate.  After she receives the letter in which he acquaints her with the Weird Sisters' predictions for his future, she hopes that he will come home quickly so that she can "pour [her] spirits in [his] ear" and convince him that he will need to do something dramatic in order to bring his destiny nearer. 

Ambition seems to motivate her plans for the future.  She wants Macbeth to be king, and the prospect of becoming queen seems quite desirable to her.  When Macbeth arrives home, she tells him, "Thy letters have transported me beyond / This ignorant present, and I feel now / The future in the instant" (1.5.64-66).  She is anxious to bring the future closer because she wants it now.