Wynoma -- where Lady Macbeth gets her Power?

MacBeth's entire relationship with Lady Macbeth is odd.  The play was written in a time when women had practically no freedoms. Lady Macbeth tells Macbeth what to do like she is the one in charge, and this is odd.  She finds out the he is a thane, and king, and all those things that just scream "power," so she becomes a little crazed for power.  Whatevey gave her the ideas that she has the power?  She is not the one to be king; she is simply the controlling woman who just happens to be married to that man.