You spend so much time with your classmates, and go through so much together that it could be easy to just stay in that little bubble.
Having them know your partner and having your partner know them just alleviates a lot of problems.
Talking to some of my (to be honest, male) classmates, it seems that a lot of their partners have a hard time with the fact that they can't always talk when they want to, which is why sometimes a set plan is best.
When I was that person, I took over a lot of the house responsibilities - I did the grocery shopping, the laundry, took care of the bills, and did the majority of the cleaning. In addition, the time that he saved from not having to do the other life responsibilities could go towards real time with me. ;) Long-distance relationships, on the other hand, add a whole other level of difficulty on top of what already is a hard situation.
All LDRs have their hardships, but I feel because medical students rarely get free weekends or nights that it makes it pretty hard to always stay in touch.
At the beginning of his fourth year, I moved four states away so that I could start medical school.
Three months in, we mutually agreed to end our relationship.
So for a bit of my own background: I dated a guy for 5.5 years, with 3.5 of those years spent with him in medical school.