What is the cause of the conflict between Nym and Pistol and how is this conflict resolved?

Nell Quickly had once been betrothed to Nym, but she married Pistol instead. As Nym and Pistol begin to confront each other with swords, Bardolph uses his senior military ranking to demand an end to the duel. Nym and Pistol are also distracted by the news that their friend, Sir John Falstaff, is dying.