If you're looking to accomplish something, say a fitness goal or personal goal, why not look to your partner to be your personal coach. Even better, why not both pick a goal and coach each other.

Let's say one of you wants to learn a new sport while the other wants to master cooking. You could both sign up for lessons and then motivate the other to attend all the classes, practice, and master the skill.

In the end you'll both grow and develop as a couple. Isn't that what relationships are all about?