What I think of Macbeth?

I have never read Macbeth before so I am looking forward to Reading it. So far it is very very good and I hope that lady Macbeth gets what she deserves in the end. One thing that confuses me is why can't Macbeth become the man in his marriage and tell his wife that he doesn't want to kill King Duncan. If he can be a hero on the battle field then why is his wife such an impossible foe for him to defeat. Unfortunately it is to late because he has already killed the king.