Shakespeare uses this contrast to emphasise the lack of feminine qualities in Lady Macbeth, which is vital to the drama of the play, as it is Lady Macbeth's influence, as a result of her personality, which greatly contributes to Macbeth developing the fatal flaws which eventually led to him committing acts of murder, upsetting the natural order, and ultimately to his downfall.
Another relationship which is Shakespeare uses to intensify his drama, is that of Duncan and Macbeth, as seen in act 1. Macbeth is essentially a war hero, and a great man in Duncan's eyes. In Act 1, scene 2, Macbeth is praised profoundly by King Duncan, who speaks of Macbeth as a "Worthy man." The relationship in this scene is mutual, as Macbeth also respects his king. However, it is later on, when Macbeth starts to become more ambitious, that he eventually murders his own king, which was a terrible crime, during that time period. Through the betrayal of this friendship/relationship, the plot of the play changes suddenly with a major change occurring in the protagonist Macbeth, whose character changes drastically. After killing the king, he felt empowered which led to him murdering more people. This feeling of empowerment also led to him doing things on his own and not letting his wife boss him around, developing a sense of independence. Even when he is facing his final battle which he knows he will lose, he yells "At least we'll die with harness on our back", implying that he plans on fighting to the death and taking a few people down with him. In this manner, it is seen as a very honourable death. By this time, Macbeth and Lady Macbeth had grown very apart and he did not seem very affected when Seyton informed him, "The Queen, my lord, is dead." As can be clearly concluded from this, the Drama strengthened SIGNIFICANTLY at the point of betrayal in the relationship between Macbeth and Duncan, and so without the development of this relationship, the play would've taken such a sudden turn, which wouldn't really have been dramatic at all.