It depends on the couple. Like some have said earlier, if the couple have similar attitudes towards studying and both want to do well it could be beneficial but to a couple with very different attitudes where one person never wants to study they could be a distraction to their boyfriend/girlfriend. I think a thing to remember is these are high school relationships, people are subject to change and people want to go down different paths in their lives. It is not going to be the end of the world if a person goes through a break up during their HSC. Yes, it will be upsetting but personally I'd use it as an opportunity to study my heart out and distract myself in other ways. Well, that's how I handled my last break up and my school marks improved but that won't be the same for everybody. I know this sounds cold and mean but I think partly understanding things may not last could make the break up process easier. It will be easier to accept and move on if you haven't had your head in the clouds thinking you're going to marry this person and spend the rest of your life with them.