Gauri is someone who has a very deep seated inferiority complex. She was very poor since childhood. Then the child marriage and the rejection. It scarred her psyche. Her parents added to her woes by keeping the wounds fresh. As a result of all this I guess they ended up spoiling her and she became arrogant and headstrong. When she got her degree she became proud and more arrogant and to a certain extent that inferiority complex transformed into a "pseudo-superiority" complex.
When a person grows up - they need to be able to differentiate right from wrong. Gauri has proved she does not want to do the right thing. She could have walked away from the relationship but she wanted to prove a point to the Singhs and to Anandi. Somewhere in her mind, she is taking what is rightly hers but she fails to realize that Jagat is not a thing. He is a person. She chose to ignore that she was destroying another woman's life - someone who was not as qualified as she was, someone who was not as independent as she was and most of all someone to whom Jagat was her world.
Gauri is highly insecure and her insecurity manifests itself in various ways. She insults anyone whom she sees as a threat. She manipulates situations to her advantage and she tries to keep anyone away who could threaten her status quo. She lacks a sense of security and she will never have a sense of security because she can never completely trust Jagat.
Her inability to feel secure, her inability to trust and her inferiority complex will ensure that she will never remain happy. She is her biggest enemy.
The sad irony is that Anandi has achieved a lot because she is finally free from the millstone around her neck aka Jagya and Gauri will not be able to achieve her objective because millstone Jagya is now around her neck. 😕 Her love for Jagya is her weakness and she will play games to keep her with him. This will prove to be her ultimate downfall.