Might be unpopular but I felt Geetanjali was always fond of Armaan right from first episode of leap. There were subtle indications of her liking in many scenes in Mount Abu. Due to this reason, her affection towards Maira always looked like a cover up to get Armaan (her Daadu himself knew she likes/loves Armaan so only was ready to arrange her engagement with him without even asking her or Armaan
) . She told Abhira, Armaan never asked her help and she voluntarily helped him always and counted all the ehsaan she did to Maira
When Armaan asked her for marriage, without even knowing about his marital status or background, she agreed immediately knowing very well, he was doing this only for Maira. Armaan clearly told her the reason for marriage, mentioned he didn't want to give false hopes to her and will never give wife rights. He also mentioned Maira's mother deosn't know about their where abouts and he has been hiding it from her. She appreciated his honesty and willingly got engaged knowing her position in his life. I would also like to call out her Daadu who wanted to get her married to a single father without knowing anything about him
Her love for Maira was also conditional and changed eventually when today she didn't hesitate to kill her 
She married Armaan by threatening to suicide, blackmailing him to separate Maira and Abhira because she was desperate to get him at any cost. Post that she had made him uncomfortable many times claiming her haq as wife, lied to him at instances, manipulated Vidya maa (researched well about her history
) , tried violating the deal that she will stay away from Maira 
Geetanjali even before they got engaged used to subtly hold Armaan's hands and he used to remove it politely so she knew he wasn't comfortable even as a friend with such friendly gestures.
Final nail in the coffin was she taking advantage of Armaan in his intoxicated state, violating his physical boundaries and didn't bother for his consent or will only to tick her definition of "completing the marriage" 
DKP's team of writers need to be called out for showing women in such poor light. There was no logical reasoning behind Geetanjali's obsession with Armaan when he has always maintained boundaries with her.
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