How do the Friar's motives differ from the couple's motives in Romeo and Juliet?

In William Shakespeare's play, Romeo and Juliet, Friar Laurence is a good friend and supplementary father figure to Romeo. The young man is distant from his own father (as most noble children of the Renaissance were) and he instead seeks guidance and praise from Friar Laurence. When Romeo comes to the Friar and tells him that he is in love with Juliet and wishes to marry her, Friar Laurence is a little suspicious. He accuses Romeo of being quick to fall in love, but accepts Romeo's assertion that what he has with Juliet is true. He agrees to marry them, if Romeo can find a way to sneak Juliet to the Friar's cell. In Act II, Scene IV, Friar Laurence acknowledges that it is a bit of a risk to marry the young lovers, but he hopes that their union will put an end to the fighting between their houses.

It could be said that Friar Laurence has the greater good at heart in agreeing to marry Romeo and Juliet. Even though they can only be married in secret, without the consent or participation of their families, the Friar hopes that these small sins will be outweighed by putting an end to the Montague-Capulet feud. Imagine the lives that will be saved, the peace restored in Verona, if only these two families would call it off! 

Romeo and Juliet do not have such long-term or big picture aspirations for their marriage, they just want to be together. Their desire for physical intimacy with one another, made apparent by their rush to share a first kiss, is a big factor in their motivation to be married. Renaissance Verona was a very religious society, and it would have been sinful for the two to be intimate outside of marriage. Though Romeo and Juliet do not really know very much about one another, they are infatuated. It might be better to say that they are in love with the idea of being in love, and becoming married would allow them to legitimately fulfill that dream. I think that Romeo and Juliet have both put a lot of pressure on themselves with regards to relationships, and marriage seems like the obvious choice for both of them to "succeed" at being in a relationship.