The wedding that occurs at the end of Act II of this excellent tragedy seems to have definite consequences that are unfortunately wholly negative for both Romeo and Juliet. Of course, the irony of this wedding, of which the Friar has such high hopes, is that it actually makes the situation that both Romeo and Juliet separately face more complex than helping to alleviate the tension between their two houses. For us as an audience, our biggest question is why on earth was this wedding kept secret? If they had declared what they would have done, the ensuing tragedy could have been averted. However, at the same time, if we look at Act II scene 6, we can see how the wedding ties in with the overall theme of fate and destiny in the play. Note the way that Romeo almost challenges fate to do its worst:
Do thou but close our hands with holy words,
Then love-devouring death do what he dare--
It is enough I may but call her mine.
Of course, "love-devouring death" does take up this challenge and perhaps make Romeo regret his words.
Let us note, however, the way that this feeds into the complexities of the plot. Firstly, the marriage to Juliet means that Romeo does not attack Tybalt yet tries to pacify him in Act III scene 1, which of course provokes Mercutio to attack Tybalt on Romeo's behalf. Mercutio's murder then triggers Romeo's killing of Tybalt. Juliet is not free from the impact of their marriage either, as Act III scene 5 shows, when she is told in no uncertain terms that she must marry Paris, when she is already secretly married. This of course triggers her visit to the Friar and his plan to somehow wrestle a happy ending out of these circumstances.