A prominent theme in Romeo and Juliet is fate, people contribute to it without knowing it and no one can stop it. The Montague house is the house of Romeo, and their enemy is the Capulet house, the house of Juliet. Romeo and Juliet fall in love, but of course, this becomes a problem because they are from families that hate each other. Fate is responsible for them meeting, falling in love, and finally dying. The Capulet family does certain things that inevitably lead to Juliet's death and the Montague family does certain things that result in the damnation of Romeo. Even Romeo and Juliet cannot stop fate, all the things they do lead them to their deaths whether they know it or not.
The Capulet house is responsible for Romeo's fate. Though they may not know it, the things they do and actions they take lead to the death of Romeo. The Montagues hate the Capulets to an extensive amount, in act 2.Sc 1.Line 81, Capulet says "Thou villain Capulet!- Hold me not; Let me go." This shows that he  thinks of the Capulets as villains, evil and wrong opponents. This also shows that the two houses get into quarrels frequently, Montague is being held captive by the Capulets. If the Montague house didn't hate the Capulet house, Romeo and Juliet wouldn't have to hide their relationship because of their differences and they could have gotten married publicly. Then, Juliet wouldn't have to marry Paris and fake her own death. But unfortunately, the two houses hate each other very much and would never allow Romeo and Juliet to marry. Ironically, The Montagues are responsible for Romeo meeting Juliet, they try to cheer up Romeo because he is heart broken when the girl he loves decides to become a nun by bringing him to the banquet where he meets Juliet. The Montagues push Romeo to be happier because they are worried about his wellbeing. For example, in Act 1.Sc 1.Line 134-136, Montague speaks about how much distress Romeo is in. "Many a morning hath he there been seen, with tears augmenting the fresh morning's dew, adding to clouds more clouds with his deep sighs." This exemplifies Montague's concern for Romeo. Though in the beginning the Montagues are concerned about Romeo, they don't pay much attention to him and his love life during the rest of the play. In fact, we don't hear from Lady or Lord Montague for the rest of the play. If they paid attention to Romeo's life and asked questions about it, they could have stopped Romeo from seeing Juliet and he would have lived. But of course fate didn't allow that to happen and Romeo continued to date Juliet in secret, leading the both of them to their deaths. In conclusion, the Montagues contribute to the death of Romeo under fates will.
The Capulet house is responsible for Juliet's fate. The things they do and force others to do are commanded by fate and result in Juliet's death. If the Capulet house didn't hate the Montagues, Romeo and Juliet wouldn't have to keep their relationship a secret. When Juliet finds out that Romeo is a Montague, she realizes how difficult and complicated her life will be with Romeo. In Act 1.Sc 5.Line 152, when Juliet finds out from Nurse that Romeo is a Montague, Juliet says "My only love sprung from my only hate!" By this, she means that her life will become unfortunately complex and secretive because the person she loves is the person she is supposed to hate. Even if Juliet was open about her relationship with Romeo, her parents certainly wouldn't let them be together. Juliet's dad, Lord Capulet, a cruel and manipulative man forces Juliet to marry Paris because of his high position in social class and wealth. In Act 3.Sc 5. Line 166-168, Lord Capulet makes it clear that Juliet must marry Paris. "Hang thee, young disobedient wreth! I tell thee what: get thee to church o'Thursday, or never after look me in the face." Opposite Lord and Lady Montague, the Capulets would never allow Juliet marry Romeo because they want her to marry an important and wealthy man rather than a man she loves. As a result of her desperateness from the  situation, Juliet pretends to kill herself with the help of Friar Lawrence. Romeo is supposed to receive a letter from Friar Lawrence notifying him about the situation, but fate doesn't allow that and Romeo receives news of Juliet's death and becomes hysterical. He visits Juliet's grave and ignorantly kills himself to be alongside his "dead" wife. Later, Juliet wakes up and finds Romeo dead so she recklessly decides to also kill herself because she as well cannot bare life without her partner. All in all, the Capulets help seal Juliet's fate without knowing it.
Romeo and Juliet cannot prevent their own deaths. The couple cannot decide what to do by themselves without being victims of fate even though they are technically in control of their own lives. Romeo and Juliet would still be alive if they didn't rush things. Because they do things so quickly, they are very committed to each other. In Act 2.Sc 6.Line 11-14, Friar Lawrence tries to explain to them the importance of taking things slowly. He says, "The sweetest honey is loathsome in his own deliciousness and in the taste confounds the appetite. Therefore, love moderately." This explains how moving too quickly in a relationship is unhealthy and will destroy the relationship. If they didn't rush things, they wouldn't be so committed and obsessed with each other. Romeo is especially reckless in their relationship, he is so desperate to fill the hole in his heart that Rosaline left that he quickly "falls in love" with the first girl he gets to know after his state of isolation and depression. He was clearly being reckless with Juliet because just before the banquet where he meets Juliet, in Act 1.Sc 4.Line 25-26, he says "Is love a tender thing? It is too rough, too rude, too boist'rous, and it pricks like thorn." This shows that just before he "falls in love", he believed love was evil and he wanted nothing to do with it. Romeo's impatience is responsible for the death or himself and Juliet. If Romeo had waited a little longer and processed what happened to Juliet when he found out she was dead, he would have gotten the letter that informed him that Juliet's death was fake and intentional. However, not all the blame is for Romeo, Juliet also played a part in the tragedy. If Juliet hadn't overreacted and faked her death in the first place, Romeo wouldn't have killed himself and she wouldn't have either. To sum up, even Romeo and Juliet couldn't change their own destiny.
In conclusion, Fate plays an important part in the tragedy of Romeo and Juliet. Shakespeare clearly believed in fate and destiny, that all the choices you make in your life lead to one event set in time that is inevitably going to happen. There is no way to prove that fate is real, but if it is, I think it is irrelevant. Like Romeo and Juliet, no one would be able to change their fate so it does not matter. However, you cannot blame fate for the choices you make in life. You still have choices and different opportunities to make by yourself. All in all, you can control what you do in your life and even though you can't control your fate, you don't have to pay attention to it.