My dh is in his last year of grad school. I'm lucky in that the actual hours he puts in aren't too bad, but with a dissertation hanging over his head, I feel like work eats up a lot of his mental energy, even when he's home. He sets very high standards for himself and then uses his free time to feel guilty about not working, instead of letting himself really relax and just be happy.
We've been married for 9 years, through different jobs and grad school for both of us, and now that he's doing what he loves and we have a wonderful 6 month old dd and a great home, I just wish that he could let himself enjoy it all more. I really believe that happiness should be the primary meaure of success, but I think it's easy to get caught up in using careers, salaries, and comparisons with others to define ourselves.
Sorry if I sound negative, but I love him so much and wish he was more mentally present in enjoying our little girl and just living life with us.