C is really a loser who wants to win all the time in anything she does. She thinks she can own people the way she owns material things. She keeps talking about her undying love for TA and her desire to marry him, and justifies everything she did by laying claim to 'owning' TA. It's true that the fact that she became psychotic was triggered by her 'failure' to 'own' TA legally by marriage. ut she never ever stops to think that he is a person with feelings and he chose someone else-plain and easy. Ok, the way he did it, by marrying T without explaining to C before it happened was not the best way and it was indeed circumstantial. However, I believe that even if TA had explained to her that he simply DOES NOT have feelings for her, she will still not get it into her thick skull because she only thinks of things from her point of view, and in terms of what she wants, and what she needs. He's just a commodity she needs to possess like everything else in her life.
Even in this episode, when it's plain clear that he does not harbour the same feelings for her, she still pretends and shuts out reality. She even gets 'shocked' that he would deny that she is his wife. She tells TA that she did everything she did for his happiness. She shuts out the reality that his happiness is T.