In scene 7 lady Macbeth is trying to persuade Macbeth into killing the king because Macbeth is having second thoughts.  I know this becabuse Macbeth says we will go no further in this business.

Lady Macbeth will start to feel betrayed because every since Macbeth said he might become king lady Macbeth had been talking about it all the time time, to Macbeth anyway. Another reason lady Macbeth would feel betrayed is because lady Macbeth says live a coward