Why does Romeo threaten to kill himself?

After the violence that opens act 3 which leaves both Mercutio and Tybalt dead, Romeo seeks sanctuary at Friar Laurence's cell. In act 3, scene 3, the Friar informs Romeo that the Prince has not sentenced Romeo to death for fighting in the streets, as he had promised in act 1. Instead, the Prince has condemned Romeo to be banished from the city of Verona. While Friar Laurence tries to portray the verdict as positive, Romeo immediately launches into a tirade bitterly complaining that death would be more lenient than exile from Verona, without the ability to see Juliet. He says,

There is no world without Verona wallsBut purgatory, torture, hell itself.Hence “banishèd” is “banished from the world,”And world’s exile is death. Then “banishèd”Is death mistermed. Calling death “banishèd,”Thou cutt’st my head off with a golden axAnd smilest upon the stroke that murders me.

When the Nurse comes, Romeo immediately inquires about Juliet. The Nurse replies that Juliet "weeps and weeps," calling out the names of Tybalt and Romeo. Romeo counters that he would gladly kill himself if he had caused pain to Juliet, comparing himself to a "hateful mansion" where his name lives:


As if that name,Shot from the deadly level of a gun,Did murder her, as that name’s cursèd handMurdered her kinsman.—O, tell me, friar, tell me,In what vile part of this anatomyDoth my name lodge? Tell me, that I may sackThe hateful mansion.




Following these lines, the stage directions state, "He draws his dagger" suggesting that Romeo is poised to stab himself (in a bit of foreshadowing, as Juliet will later use the same dagger to kill herself). Friar Laurence stops him, arguing that Romeo's "tears are womanish" and he should actually be grateful for the circumstances. He reminds Romeo that he lives while Tybalt is dead and that the Prince has foregone death for banishment. He advises Romeo to go to Mantua, let time pass until the Friar thinks things have become less volatile, and then they will announce the marriage, seek a pardon from the Prince, and Romeo will return "With twenty hundred thousand times more joy / Than thou went’st forth in lamentation."