And when she was going to be disrobed that was gross Adharma and any of the 5 Pandavas could have stood up and stopped this but they did not. It is the Dharma of a husband to protect his wife at any condition..that too in a situation where one's wife's honour is at stake. So the Pandavas didnt honour their own Dharma as husbands to Draupadi. Just imagine if it was Kunti that was going to be disrobed I am 100% sure the Pandavas would have killed the Kauravas there itself.