Who was to blame for the tragic deaths of Romeo and Juliet? Two star-crossed lovers with a forbidden love and so many obstacles to overcome, but in the end it wasn't enough. Was it the fault of the two families and their bitter feud, or perhaps the Friar and the Nurse, or was it all just destiny in the two young lover's fate... From forth the fatal loins of these two foes
A pair of star-crossed lovers take their life,
Whose misadventured piteous overthrows
Doth with their death bury their parents' strife. (Prologue, 8-11)
Some people argue that it was the Nurse and Friar Laurence's responsibility. They are after all the ones who encouraged the relationship to begin with, so technically the problem started with them. Friar Laurence, although sceptical about the union when Romeo first informs him of it, Is Rosaline, that thou didst love so dear, so soon forsaken? (II, 3, 70-71), quickly agrees to happily marry them, thinking that this might end the ongoing feud. For this alliance may so happy prove to turn your households' fancour to pure love. (II, 3, 98-99)
The Nurse plays just as eminent a role as the Friar in the forbidden marriage of the couple, making all the arrangements in secret from the Capulet's. She also changes her mind about Juliet and Romeo after he is banished from Verona, and then sides with Juliet's parents, agreeing with them that she should marry Paris, only driving Juliet away even more so. I think it best you married with the County. O, he's a lovely gentleman! Romeo's a dishclout to him. (III, 5, 204-205)
Upon marrying them at the secret ceremony in his cell, Friar Laurence does advise them against unbridled passion which shows that he cared about the consequences of these actions about to be performed, however it also foretold the sense of doom of the situation which the Friar should have seen. These violent delights have violent ends...