What destroys the relationship is that Lady MacBeth can't control what she has inspired.
In Gaudy Night, Dorothy Sayers's characters discuss what happens when one spouse limits or pulls down the other, either intentionally or unintentionally. The problem with MacBeth entails the opposite behavior (one spouse pushes rather than limits the other) but it relates to the first: one couple is trying to design or fix or otherwise manufacture a "perfect" spouse. In Lady MacBeth's case, that perfect spouse is a king. In another case, a perfect spouse might be one who doesn't do that type of work or write that type of stuff or spend time on those kind of causes.
The ambitions are different but the behavior is the same: trying to organize someone else's life to make one's own life feel organized.
I suggest, as have others, that even if MacBeth hadn't turned into a nut-case, he still would have failed Lady MacBeth. Again, actions don't have tidy consequences. Eventually, she would have become another enemy, another person standing in his way. It was only a matter of time.
Better, truly, for people to know what they are marrying than to try to force a spouse towards what they imagine they are marrying.
*MacBeth is one of those plays that works at the narrative level, no matter what its trappings--like Cinderella or Beauty and the Beast. A number of mystery shows have "done" Lady MacBeth, including Jake & the Fatman, Season 1, "Rhapsody in Blue." Strong parts for many actors!
