Have a serious talk with your significant other before going away. Make sure you are on the same page with regards to devotion to the relationship, willingness to work through issues. etc. That, I think, is key--not only for the confidence you get from such a conversation, but also for both of you to establish parameters/priorities.
Many people in my class are still together with their long-distance SOs and are doing well. As for myself, I went through a two-month long breakup, and was emotionally reamed six ways from Sunday trying desperately to make it work with someone who just really couldn't handle the distance. And because I was so hell-bent on making my relationship work, and devoting so much time and energy to it, I ended up (inadvertantly) isolating myself from my classmates. Now I have no boyfriend, no social network, no friends here, and still cry just about every day and feel like there's nobody here I can talk to. (I don't want to burden people I don't know very well with my not-insignificant problems.) On top of vet school stress.
Not fun--you do NOT want to go through what I have gone through. TALK TO YOUR SO before leaving. And make sure to build your OWN LIFE at vet school.
At least I can say that I tried everything I could. However, there were warning signs beforehand--he was always more scared of the distance than was--so be prepared if your SO has a wishy-washy state before you even leave.
I think the difference between the couples that work and the couples that don't is the willingness on BOTH sides to work through the problems that come with distance. On the good side of things, in the early days of vet school (when things were going well with myself and my BF), I felt so supported and happy and lucky.
It was hard, sure, but it was AWESOME. So if you can keep that up, it'll be great--as others have said, enough time for studying, but also fulfillment in your personal life. "Vet school stress" didn't really exist for me back then, because I had a rock to lean on. Hopefully, you will be the same way--only for much longer!
At the end of the day, though, no matterwhat you WILL be a veterinarian. Those who say that if a guy/girl can't handle the distance, then they don't deserve you are correct. Those who say, too, that you should follow your dreams first and a relationshp second are also right.
Sorry to be such a downer. One of my best friends goes to vet school at Murdoch, and she and her husband just got divorced. Again, because there was a difference in the levels of commitment/desire to work through problems. I cannot emphasize enough how important this is!
Good luck to all of you in school and your relationships.
It really is a wonderful thing if/when it works!!