Have you noticed anything like this?
By interacting with your dual, you learn more about yourself, and who you are supposed to be, not only to "them" but also in the world?
Because they naturally need you to be "you", do you find yourself being drawn towards becoming something that is better than your own, solo natural state? Perhaps "better" isn't the right word, but, being around someone who needs you to be your "true self" seems to be very revealing, if you are open to it. Particularly if you are not or have not usually been around people who need such.
I am reminded of one of Rick's articles on duality.