The first turning point in A Doll's House is when Torvald reacts the way he does to Nora when he finds out about her secret. He yells, shouts and sends Nora to her room. He treats her as his child. At this point, she realizes that he does not love her as a man should love his wife, especially a wife who has risked her own reputation to save her husband's life.
The next turning point occurs when Nora asks Torvald to sit down and discuss all that has just happened between them. She points out that this is the first time in the history of their marriage that they have decided to truly communicate.
The third turning point is when Nora tells Torvald that she is leaving to find out more about herself. Nora decides to leave Torvald in hopes of finding herself, finding her own identity. Up until this point, she has been Torvald Helmer's wife. Now she is desiring to find out that she is her own person. That person is hidden way down deep inside of Nora. The only way she can find her own identity is to leave Torvald. He stifles her growth as a person. He treats her as his child, not as his wife.