Uni is anywhere between 10-30 hours a week (for full time). If this small amount of time is going to be troublesome for your relationship then there is other issues. Most people have relationships throughout uni, in fact it would be unusual for somebody to not have a relationship during the course of uni.
I honestly hate people like this. I can't have a relationship because of the HSC. I can't have a relationship due to Uni. The thing is HSC/uni/part time jobs have nothing on the pressures (e.g. time wise) of conventional career. If you can't cope with a relationship now get used to being a hermit.