Is this worth Duncan's life?

     And now I'm Queen. Was it worth it? The murder of the king will haunt me for the rest of my days, but what is done, is done. I will not think about it any longer. I should be rejoicing. I am Queen as I wanted and I have managed to do it by convincing my husband to do the dirty work, but I am afraid that it has stained him. I am afraid that he is no longer the man that I married. He now speaks of killing Banquo and Fleance without me saying a word. I no longer have the power to pull him back from the edge that I threw him over. He now continues to murder when there is practically no need. We have the throne; we should be rejoicing. Instead Macbeth goes to murder yet again. I fear I will not be able to stop him. I fear I have no more control over him. I fear we will be thrown off this throne before we have even gotten used to the luxuries it brings us.