Thats what Madhu is to RK. His only weakness. We saw it again today. He was mesmerized by Madhu until his mother's words reminded him that his heart is still vulnerable. To remind himself she is nothing to him, he makes her serve his guests like a servant.
RK. Hard as a nail on the outside, soft as a marshmallow on the inside. Anyone who comes near is bound to get hurt, that too badly.
We do get occasional hints of what he went through to make him the hard man that he is today. What ever happened pained him so much that he closed his heart to others. Now arrogance and anger are his armour. He doesnt allow others to touch his heart, let alone come close. His every action, is designed to protect his heart, a very vulnerable heart. He is afraid of opening his heart, lest someone betray his heart again.
Yet, with Madhu he cant help himself. His heart is drawn to her like a moth to a flame. A fire is sure to destroy the moth. And yet, like a moth, he is drawn, time and time again, to the fiery Madhu. He just cant help himself. Somewhere deep down he acknowledges that she alone can save his black heart. But past intervenes and makes him mistrust her.
He does only one thing that he knows will protect his heart, from the pain he knows that Madhu can inflict, should he allow her. Thats what he does. Treating her so badly until she starts to fall. Yet, his heart doesnt want her beaten down too badly. Just enough to make he fall. Not enough that it will stop her from standing again.