Your lover has set goals for themselves, and they've been working toward them, hard and steadily, all their life. They have well-defined ambitions and expectations of themselves in terms of success, but when you entered their life, you may have set all that on its end and uprooted everything. Part of the problem is that, at least outwardly, you're much less directed than they are.
Maybe they're the type of person that really wants to make a name for themselves, while you're content with being unknown in the world, doing your important work behind the scenes. Or maybe you just haven't quite decided on what it is that you want to do, while your lover knows very well where they're headed and how they're going to get there. Either way, your natural spiritual beliefs make it nearly impossible for you to understand your partner's work or career goals. This could be a problem of materialism versus spirituality -- if they're working hard toward financial stability, for example, while you believe that to be a trivial, meaningless goal in the face of more human, emotional pursuits. But treating their goals and beliefs as trivial isn't a good idea. If you want this to last, you have to find a way to accept your differences in this arena, and to try to understand each other better.