Deception in Act 3

As I was reading through Act 3 I noticed that there is a great deal of deception throughout this act and the entire play. It seems that there is a definite struggle for power throughout this play and the characters attempt to gain this power through deceit. For example, the Duchess wants to maintain the status of marriage but her marriage to Antonio is unknown to her brothers. Even when Ferdinand confronts the Duchess and she tells him he is married, she sends Antonio to safety from Ferdinand by pretending that he has stolen money and has been banished. Power in this act is marked by a need to maintain femininity, as the Duchess tricks Ferdinand into believing that Antonio is no longer a part of the Duchess' life. The Duchess longs to be married and maintain that marriage, but when that marriage is put into jeopardy, the Duchess is able to keep control or power over her relationship through the use of deceit. I was curious if anyone had any other thoughts on this idea of deception, as I find it very interesting.