By describing Romeo and Juliet as “star-crossed lovers,” Shakespeare establishes the fact that they have to be together, and they were fated to fall in love.
Although there is a struggle between choice and fate going on in this play, the prologue establishes an interesting idea. In short, it seems to be saying that in order to end this feud between the two families, their children had to die. In order for them to die, they had to fall in love.
A pair of star-cross'd lovers take their life;
Whose misadventur'd piteous overthrows
Doth, with their death, bury their parents’ strife.
The fate of Romeo and Juliet is in the stars. They were destined to fall in love. They were destined to meet tragedy. They had no control over the actual events themselves. That is what “star-crossed” means, and Shakespeare wanted us to understand this from the very beginning.
It definitely does seem as if fate is against the young lovers. First, they are born into feuding families; then, for Romeo accidentally gets invited to a party and sees Juliet. Then, Romeo accidentally kills Tybalt in a duel and the two lovers are separated when Romeo is banished. Finally, Romeo does not get the note about Juliet’s death being faked, and kills himself just before she wakes up. Ouch, that’s a run of bad luck.