Haha, I was in the exact same situation almost. What you need to do, whether you like it or not:
- Don't give her everything, criticize her a bit sometimes, even if you say it's jokingly she'll still take it seriously. Make her want to improve herself for you.
- Don't make her feel secure. Make her feel like there's constantly a small chance you might leave her, maybe even sometimes a bigger chance.
- Control her, get your way a bit. Give her an illusion that she has some power, but lay down the law quite a bit.
- Don't care about the relationship, the best way to keep it. If you keep that mindset, you'll seem as apathetic as you should be to the whole thing, this will reflect on her, and she'll constantly want to work to make you feel not apathetic.
Do not learn these lessons the hard way, follow this advice.