In each other you find a lover who encourages you and understands you, and helps you find your way. You feel as if your partner is your safe harbor, the person you can come to for inspiration and guidance in life. Their natural spontaneity and enthusiasm is an inspiration to you, and you go to them for advice because you know that they understand you so well.
You need to establish a direction for yourself, for your future, and they help you do that -- and in helping you, they define their own life path more closely. But this isn't (and shouldn't) be based on an idea that your partner knows what's what, and where you ought to go in your life; it is much wiser to take the perspective of not knowing, and simply following the signposts as they appear. Staying open to opportunities is a big part of this influence, and if you two can do that together, some amazing things result. As long as you're communicating clearly and not trying too hard to guide each other in a forceful or manipulative way, you're a real help to each other.