Deep down RK knows the damage he has caused to Madhu is grave, (they did show RK having flaskback of the "un-wedding" night). He is certainly very much aware. Reality conflicts with his wishes. He wishes Madhu back in his life but after what he has done she will obviously not return to him, therefore he denies his mistakes, he has gone into this CRAZY DENIAL MODE, It's crazy that what he has done to Madhu is now just a "nok jhok". Like seriously?? 😕
RK is dealing with powerful emotions, he is not yet ready to accept that he is in love with Madhu. Neither does he accept his mistakes because he basically wants to erase that night. He is suppressing his emotions to the point where he is almost psychotic. Burying feelings is causing him to lose his composure , as we can witness with Mr. RK. Furthermore, he does not share his feelings with anyone which is even worse, because all he feels is bottled up in his mind. His denial is giving him hope that everything is going to be okay even though their relation has almost ended. RK is crumpled inside but his denial keeps him functioning.
If he accepts his mistakes than he will also have to accept that Madhu does not want to be with him (even if she loves him), and that he broke her into a million pieces and their relation will never ever be the same. Accepting means letting go, accepting his irrevocable mistakes basically means intolerable pain for him because then he will also have to accept that he has lost Madhu's trust and their relation is back to zero. I am not sure what the creators have in mind for RK's character but I assume he foresees his guilt for putting Madhu through tremendous pain but for some reason he does not want to blame himself because he is preventing himself from getting hurt, he is very much aware of his inhuman nature towards Madhu but he is denying it because of fear of losing Madhu.
If he further continues to deny the feelings he has for Madhu than he will live a little less everyday. His denial about his relationship with Madhu is driving him to take some psychotic measures seriously. RK we all love you but that's not how you win your love back beta!