Background: I am married, and moved to a new city with my husband while he attended med school (granted, not exactly the same as LS, but similar in study intensity, etc.). I knew I wanted to go to LS, but we decided that I would work a few years first and support him through the transition, and then he would have his routine down enough that he could support me through the transition to LS. I have a full-time job that I will maintain until I go to LS in the fall.
While I am not super needy or anything, I suppose you could call me "demanding" in the sense that I expect my husband to balance school and our marriage to the best of his abilities. I still want to spend time with him, and go out on dates on the weekends, and things like that. However, I am aware that his schedule is packed, and that he is doing this not only for himself, but for our future, so when school really bears down on him, I let him be, and try to help all I can (making flash cards for him, doing late-night caffeine runs, etc. - basically, around hectic periods, I make sure all he has to worry about is school).
A few things to consider:
1)It's really important that she feels like she can let you know if she's feeling abandoned (note, not bitching and nagging, but just being informative). Knowing about her feelings early and taking an interest in addressing them will keep her from blowing them out of proportion in her head. You'd be surprised how even a mid-day text like "thinking about you" can go a long way towards making her feel "in the loop".
2) Speaking of being "in the loop" I would say that is the single biggest obstacle we faced in our transition to grad school. Although I was worried about being lonely and stuff, more of what I was worried about was feeling like our worlds were suddenly separate. Before, we were both college students, so we kept the same hours, lifestyle, etc. But when he went to Med school, all of the sudden he was still in "student mode," and I had a 9-5, so I felt oddly grown-up. He wasn't going through that, and we had to figure out a way to reconcile it.
3) I know LS is likely to be somewhat overwhelming, but keep in mind that the economy sucks right now, and finding a job is really stressful (and overwhelming)...LS is hard, but at least you KNOW you have a place to go every day. Odds are it may take her awhile to make the transition to the workforce, and she may feel like she's "riding your coattails" for awhile.
Sorry to write a short novel, but I thought my situation might give you some insight
Ultimately, it boils down to this: do you love each other enough to make it work? If that answer is yes, then rest easy...although all you hear about is the couples that break up, rest assured that it's not always the case