This relationship has a unique form and function for both of you. The emotional bond between you is similar to that between a parent and child, or a teacher and student. This is not to say that your bond is platonic, and it's definitely not to say you're not equals!
You are equals, and of course there is a romantic connection. It's just that there is also a natural potential for teaching, learning, expansion and growth in this relationship. From the start, your partner has been on an emotional growth trajectory, going through all sorts of personal changes and enlightening life lessons, and you more than likely serve as audience and guide for this journey -- and perhaps even a mirror by which they will gauge their progress. This dynamic may lead to trouble, however. You are required to provide a lot of emotional support and sensitive feedback, and could end up feeling used or taken for granted -- or even resentful of the changes and soul-growth that your partner undergoes. And they, who are growing by leaps and bounds, could take on a sort of center-stage position in the relationship that may end up squeezing you out of the spotlight. You must both be aware of this potentiality and strive to be equals, even while supporting one another's growth as emotional beings.