"Oh what a tangled web we weave / When first we practice to deceive!" (from Sir Walter Scott's Marmion)
Nora Helmer (Jane Fonda/Claire Bloom) in Henrik Ibsen's 1879 play A Doll's House, filmed twice in 1973 by Joseph Losey and Patrick Garland, respectively, knows all about that phrase. Nora tries to act like a loving, devoted wife, but is really nothing more than a deceitful liar.
Nora spends many years trying to cover up a secret from her husband, Torvald (David Warner/Anthony Hopkins). The entire problem starts when she illegally forges her father's name on a loan to pay for a trip for her husband so that his health will improve. Instead of telling her husband the truth, she lies and says the money is a gift from her father. This is where the deception begins.
Nora then has to lie to Torvald frequently in order to get money from him to pay back the loan. She begs for money to buy this and that and then uses the money to pay off the loan. When Nora finds out she is in danger of being exposed, she continues to keep the truth from her husband, instead of telling him what she has done.
Nora is viewed by many as the victim in the story because she is her husband's "doll" and plaything. Nora lives a lie because she chooses to do so. She encourages Torvald to treat her like a child because she behaves like a child. If Nora were truthful with her husband instead of hiding things from him, as children do when they have done something wrong, then things would be different for her.
Torvald has been a good husband to Nora. He has treated her very well, actually. When she asks him for something, he never denies her and is even willing to forgive her for deceiving him for so long.
I believe Nora leaves Torvald not because she wants to be independent and free, but because she is ashamed of herself for being the kind of person she is revealed to be. Her cover blown, she can no longer keep up the appearance of being a loving wife.
Nora's entire existence is nothing but deception. She has tangled herself in so many lies, she probably does not know how to act after she is discovered. That is why she plays tough in the end. In my opinion, it is just an act to save face. I did learn from her example. I never want to live a lie. The best way to keep from it is to never start