In my meandering experience, all my bfs (all 2 of them) and most of my male friends want to find someone who's perfect for them and stay with them.
I may have just been very fortunate. I think the fact that you're with someone and won't sleep with them at uni will have an effect on the guy, and slims your chances of finding someone who is willing to wait and get married before they can sleep with you. They're hormonal creatures, teenagers, and ones who will wait are very rare finds, so don't be surprised if 1 in around 8 won't be prepared to do so.
I'd have a major problem with it.
try dating catholic men?