Unlike many noble marriages at the time, the Macbeths' relationship seems to be founded on a real kind of love. When Macbeth writes to his wife, he calls her his "dearest partner of greatness" and says that he wants her to be able to begin "rejoicing" over the "greatness [that] is promised [her]." It would be pretty unusual for a husband during this period to refer to his wife—his legal, social, and religious inferior—as his partner. Next, Macbeth seems to be genuinely interested in his wife's happiness. Then, when Lady Macbeth considers the news of his letter, she calls him "great Glamis," indicating a certain respect for him (despite his being "too full o' th' milk of human kindness" in her view). When Macbeth returns home, shortly thereafter, she repeats this, calling him "Great Glamis, worthy Cawdor" (1.5.45), and he calls her his "dearest love" (1.5.49).

However, we can see how much Lady Macbeth's ambition and her husband's pride can corrupt what seems like real love. When Macbeth tries to back out of their plan, she emasculates him, implying that he isn't really a man if he won't go through with the murder. Later, when Macbeth is traumatized by the murder he's just committed, she shames him for his supposed cowardice and weakness. We see, then, that love doesn't conquer all; it can be corrupted and wasted by ambition or greed or pride. The Macbeths begin to drift further and further apart until Macbeth no longer even tells his wife his plans, let alone consults her in them.