The agony he faces can never be said in words, words will go in shortage to describe his pain. He is the true hero, what he stands by is justice. All your life you have been the prey of unjust behaviour from fate, when the whole world goes against you, leaving you alone. There was just one light for him, this was the light or his saviour which saved him from drowning, which gave him a new life and gave him what no one could give; RESPECT and ACCEPTANCE. And now one asks him to break off from that hand, throwing upon him bitter realities which at this point is and always be hard to accept. His heart bleeds, he knows the truth that he is going to fight against his own brothers. It is not easy, it is painful, and it is the harshest injustice which has hit him ever in his life. Now even if he survives, his heart will be aching, he won't be happy, he will suffer. Were these pains less for him? He is man of golden heart. He will endure the pain but will not let others go through this pain. He knows if his brothers knew the truth, they will not fight against him or even if they had to for the restoration of Dharma', then they will also go through what he is going through now and he don't want them to suffer the way he is suffering. His heart is broken into bits and no one could ever understand the pain there, it is beyond one's perspective. All the life he bear the insult of being a sootputra' and now knowing the reality of birth, he is bearing the pain of the emotional turbulence undergoing in him. He is the true HERO in every sense.
Mahabharata is an epic which teaches you beyond Dharma', it brings to you lots of human flaws and how to that one flaw could change the entire story, like how the silence of Kunti created a catastrophe and there are lot more to ponder upon.