Here, I will discuss the relationship itself.
Nearly every version of MacBeth portrays the two as a loving couple with compatible goals. I find Shakespeare's achievement here quite remarkable. With Taming of the Shrew, he directly suggests that Kate and Petruchio are equals, no matter what concessions she makes to social mores.
With MacBeth, however, he doesn't have to suggest. He simply presents the couple as equally ambitious, equally intelligent, equally cunning.Lady MacBeth's name has become synonymous with a clever woman who pushes her spouse to extremes or, at least, can't be trusted not to kill off her house guests. But unlike, say, the Whore of Babylon, she isn't alone in her bad behavior. MacBeth is as large a character as she is, so the play offers powerful roles to both the man and the woman.
I've mentioned elsewhere that Shakespeare appears to believe--even in his comedies--that every relationship is different, so even the token happy endings/marriages are between THAT woman and THAT man. With Taming of the Shrew he took a well-used trope and made it unique, distinct. It isn't just any shrewish woman and domineering man. It's THIS woman and THIS man.
He does the same with the ultimate ambitious couple. Although MacBeth-types are used over and over again in numerous murder mystery shows, those episodes usually stand out because the couple are memorable. And they are memorable because Shakespeare didn't simply throw "conniving" and "ambitious" into a bag and shake it up. The MacBeths have thought through their crimes. They are human enough to balk after the fact--to see ghosts. They are self-protective enough to keep going. And although they eventually fall apart, they could never had gone so far if they weren't--however evilly--compatible.Their murders are, in sum, character and relationship-driven.


