This person is a big source of support for your work and career. Romantically, your relationship could even take on a power-couple kind of feel, especially if you are together long-term. They take on your goals for success as their own, and they help you to develop a good public face -- wining and dining potential clients or important associates, or throwing parties to wow the neighborhood and show them that you're people to be taken seriously.
At the very least, they talk you up in public circles, advertising your work and your strengths to other people, always with the thought in mind of increasing your opportunities and your contacts. You're a really strong team in this regard, and as long as you keep each other motivated toward success and keep communicating clearly and well with each other about your connection and your ambitions, you stand a great chance of lasting long into the future, and at least of making a big and lasting impression on each other's lives.