I'm not even sure that he and Geet even had a casual relationship. Most probably a one-sided crush from Geet which Anshuman found cute and childish considering her nature. He never reciprocated his love but Geet being an idiot ran away from her home even without telling him anything. She probably thought that he would have to accept her considering that she left everything for him, just like it happens in movies. But when he rejected her love and whatever sacrifice she thought she was giving for him, reality struck her and she realized that this is real life, not a feature film.
But still Aditya painted Anshuman as a jerk who used Geet. When actually there was no fault of his that a crazy girl is in love with him but he doesn't feel the same way about her. Geet calling him and abusing him after so many months just made him feel guilty of being the cause of her sufferings. He was ready to marry Geet only to save her honour and also that she could return back to her family. But then at the last moment Geet realizes that no, she actually loves Aditya and ditches Anshuman. Doesn't even apologize to him for causing him so much trouble. How can anyone not feel bad for this guy? I legit felt sad for him that he got caught up in the mess of two confused people who are not sure about their feelings.
I also don't know why the character of Geet is glorified and loved so much when she nothing more than an IDIOT!!!
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