Okay, maybe not.
This is me and my crazies talking but,
could it be that RK has dissociative personality disorder?
Better known as split personality.
He was Rishabh, the caring kind, all this time.
Now, he has shifted back to RK, the devil who protects the past held within his unconscious.
In his compartmentalized personas, he has hidden parts of himself that his whole does not wish to recollect. He lived as RK, the superstar who excels in his craft of acting. He put on that facade to become acceptable in the society. Along came Madhu and he changed, opened up as best as he could. His otherwise repressed persona came out. Now, he is getting too meek, sheepish, mushy,etc because Rishabh is taking over RK. He does not want this. Rishabh's past is anxiety producing. The only coping mechanism is to regress back to what has worked with everyone before: turn into RK.
Rishabh, the family man who loves his wife and mother, is pushed back in favour of the mad man who can survive. Madhu is the one person who can see all his characters and is victimized in the process.
*I am no psychologist so, pardon the theory loopholes as long as you get the point😊