So... here is the chapter 3 and completely from Kartik's POV and I hope it make sense about his behaviour.
Chapter III::Ahsaan Hai Uska Jo Mujhko Mujhse Mila De
Roaming around the city aimlessly, Kartik carries on walking without any intention of going back. He doesn't even know where he will go but knows for sure going back there is not an option. Since he woke up his life has turned upside down. From finding out to being in an accident, having a husband, forgetting about said husband and losing 3 years of his life was just too much to deal with.
Kartik has spent so much time wrecking his brain trying to find something, anything that would verify what he is being told but was unsuccessful. It seems as if someone plucked him from his universe and dropped him in an alternate universe, where he has everything he ever wished for, which is too good to be true which is why Kartik is having hard time believing it.
Opening his eyes in the hospital with nothing but confusion on his mind and a stranger holding onto him. Kartik knows he made a huge blunder when he asks the man about his identity, he watches as series of emotions go through his eyes and dawns to him that Kartik doesn't recognise him.
3 years?! How the hell did he missed 3 years of his life. He sits on his bed trying to wrap his head around everything that Dr Keshav just told him, starting from the date and slowly building up to his accident, oh and yes, he is married to Aman Tripathi. The man who was here when Kartik woke up from what felt like years of deep sleep. He tried to look around but with Dr Keshav and staff the man soundlessly slipped from his room yet to be returned.
Kartik doesn't remember falling asleep, next time he is awake is when Dr Keshav returns to conduct check up before he is allowed to go home. Home. Kartik doesn't remember home, he doesn't even remember where are they living or he remembers his last address which for him was yesterday. Dr Keshav assures him that Aman will take care of him and will take him home.
"Gh...ghar chalein?" 'Ghar,' it was terrifying to even think about that, lost in his own thoughts he follows the other man quietly. Kartik doesn't need to look to know Aman's eyes on him but he ignored them in favour of preparing himself for what's to come. Home, their home or rather Aman's Kartik's home and he is not Aman's Kartik.
'Home is where your heart is.' Kartik has heard that countless times and today he is witnessing it, the difference between home and house can't be more visible as he looks around. Every inch of that apartment is telling tale of life of Kartik and Aman, but sadly, Kartik is unable to connect to any of it, then it's too much for him to take, he feels as if the walls are closing up on him trapping him. Suddenly, arms around him, holding him, warmth filling around him and a soothing voice to help him, to calm down. Coming back he realises that Aman is holding him, whispering to him gently and for a single moment Kartik is at peace, losing himself in those arms. Finally he looks into those eyes which have been following him since he woke up; the love, the warmth, pain, and pure longing, all emotions are so clear in other man's eyes and it's all for Kartik or at least he thought so.
Just like that the spell is broken with a sudden realisation that he doesn't know this man and this love, warmth, it's not for him but Aman's Kartik and he cannot be Aman's Kartik, he doesn't know how to be. Suddenly finding himself attached to someone who is so caring, afraid to lose him and the love dripping from his each action scares Kartik to his core. 'It cannot be true, I was never this lucky,' this thought triggers series of times where he was forced to believe that he will never get his happy ending, he will never find who would love him like this. His father's taunts ringing loud and clear in his ears, every negative comment, taunt fills his ears.
Kartik does the logical thing; pushes Aman away, literally and figuratively. Firstly breaking away from those arms even though a part of hin fights for it but he doesn't listen, he starts to ignore the only person who could help him.
Aman insists for Kartik to stay in the bedroom as other man shifts into guest room. 'What is he trying to achieve? Staying in this room will stir up memories?' Alone, on his or rather their bed, unable to sleep, he would spend hours staring at the ceiling not able to look at any other corner because all of it was reminder of the life he has forgotten. 'Or maybe it is an alternate universe.'
Aman's longing, his hopeful gaze whenever Kartik would be looking around, his physical restrain to touch Kartik is very visible, even though it is hurting Aman, it hurts Kartik even more when their eyes would meet and Aman's hope turns into ashes.
Kartik kept pushing him away to avoid this, barely acknowledging him because it would mean talking which was not possible for Kartik. His mind constantly filled with negative thoughts, when it wasn't occupied with those hateful thoughts, his mind would keep going back to Aman and how much he is causing hurt to this lovely human being who is nothing but being patient with him.
Nights are the worst because he is unable to shut off his thoughts for a single moment, until, one night he notices a shadow under the door, the shadow wouldn't move until morning and that night Kartik's mind calms down as he focuses on the life on the other side of door until he falls into dreamless slumber. Every night he would wait for the shadow on the other side of door, lulling him into a deep slumber. Few times he debated to open the door but it would meaning opening the door to every other thing which they have been tip toeing.
First time since he stepped into their apartment, Kartik feels brave enough to spend his early morning looking around the apartment, he does notices few things or rather picture frames missing from their place which he had briefly noticed first time when he was brought here. The apartment surely has its own style and vibe, Kartik can almost predict that he would have big hand in picking out most of stuff currently residing in this apartment.
Stepping into kitchen he notices the pictures on fridge hanging with fridge magnets. A warmth spread across his body looking at those pictures, nothing but love can be seen in their eyes for each other causing an almost smile on his lips. He is hit by a sudden urge to touch those pictures, to feel them if they are real or is it his imagination. 'Is this really my life? Did I actually got this lucky?' But then another voice hits his mind 'Tune apne baap ke mouh pe tamacha mara hai, ab dekh yeh duniya tere mouh par tamacha maregi. Tujhe kisi ka pyaar nahi milega dekh lena.' And just like he is back into his teenage years; alone, abandoned, bruised and broken. (This is how you humiliate your father. Just watch now, how this world will humiliate you. You will never have anyone's love, remember that.)
"Yeh humari first date thi..." Aman's soothing voice startles him. Aman starts to recite story of each picture on the fridge but Kartik is unable to concentrate because the taunting, the voices in his head are getting louder and vicious. When Aman tries to console him, saying everything will be alright unable to take it anymore Kartik just looses it. Everything is too much, too noisy, too suffocating and Kartik is not able to take all of that ends up lashing out at Aman.
"Yeh sab tumhari zindagi hogi, meri nahi hai... kuch yaad nahi hai mujhe aur yeh sab mujhe bas pareshaan kar rahi hain. Yeh ghar, har cheez. tum bhi." (This all is your life, not mine... I don't remember everything and all this is making me upset. This house. Everything. Even you.)
"Dam ghut raha hai yahan mera... mujhe jana hai yahan se." He is already spiralling into his dark hole yet again, but he cannot take Aman down with him so he walks out of there. (I feel suffocated here... I want to leave from here.)
Dawn starting to turn into dusk and his feet are becoming heavier with each step as his strength finally giving up but with his inner turmoil still going too strong Kartik pays no attention to his physical pain and attempts to keep on walking but ends up dashing into another person almost falling over.
"Abey aandhey! Dikhayi nahi deta kya?" An apology escapes his lips as he struggles to stay on his feet, world almost going black. He hears a gut muttering as he walks away. Looking around he finds himself by the river not even remembering how he ended up here. He looks at the river, the water flowing, tempted to go towards it or rather walking in it, giving himself to flowing water but his feet are no longer supporting his idea. 'So this is my punishment? Do I really not deserve anyone's love?' It starts another chain of thoughts which he is unable to deal with and his body gives out due to exhaustion, before his can body hit the path a pair of hands manage to hold him. He manages to keep his eyes open to see a familiar face smiling down at him through the tears. (Hey! Are you blind?)
"Devika?" She pulls him in a tight hug and finally he closes his eyes let his exhaustion take over him completely.
So sorry for such a angst filled chapter... I promise, it'll be okay in the end. :)