I feel both of them have feeling for each others from the beginning
Since they were fighting together
Although he always said that he hated seeing her because she reminded him with his wound but he never meant to harm her. Even when it got too far from him and she was stuck on the roof he rescued her and blamed himself for hurting her. and he changed his with her afterward
When she was preparing for his birthday in his office and he came drunk she couldn't leave him there even when her mother in-law came and saw them there and got mad at her. But she couldn't leave him just in the office alone without handing him to his brother
They both always cared for each others and felt each others' pain because they both bounded with the hurt and the pain they shared together by their partners
But they both never ever thought they could love again that is why they both never thought of the possibility that they both have feeling for each other
After Adi's moved on and faced himself and realized his feeling for her but she didn't yet