Well, 15 miles will suddenly feel like the other side of the planet idf you get here.. "further than GIRTON? Well, I'm not bothering with that..."
Seriously, people here can manage to keep relationships going. This has been commented on recently in the two student papers, TCS and Varsity. A comedy letter in one, from a girl, explained how a male friend had kept a long distance (Leeds) relationship going, and that they obviously loved each other because he had only cheated on his girlfriend with her twice!
Anyway, relationships can work. People at college now are in them- people I know from sixth form are still together, despite being at Aberystwyth and Glasgow. If its a proper relationship then it will last.