When Lady Macbeth dies, Macbeth stops briefly to consider her, and confront his own mortality.
When Macbeth finds out that his wife has died, his reaction is very poetic. He says, “she should have died hereafter” (p. 84). He then continues to make a speech that shows he actually feels some remorse, but also pities himself.
Tomorrow, and tomorrow, and tomorrow
Creeps in this petty pace from day to day
To the last syllable of recorded time;
And all our yesterdays have lighted fools
The way to dusty death. (Act 5, scene 5, enotes pdf, p. 84)
He says that life is “a told by an idiot, full of sound and fury, signifying nothing” (p. 84). Life is meaningless, after all. Macbeth is confronting his own mortality. Lady Macbeth spurs him on, but he does love her. He realizes that the end is near, and her death helps him recognize it. He regrets that he did not have more time to spend with her, and that their life was not more peaceful. Their dreams did not come true.