You'll both enjoy each other's company, and you'll generate a lot of energy when you're together. For this reason, you'll need to direct that energy in a conscious, positive way, because there will be a certain level of competition between you. It will be much better to focus it toward a particular objective than to allow it to slowly change your good feelings toward each other!
Still, even if you aren't careful in how you use this energy, the challenging potential of this particular influence shouldn't be too difficult to deal with. At most, you could become annoyed with each other because of the kidding way you'll have with each other. At times, the barbs you'll toss each other's way could be just a little too sharp; in those moments, you'll have to rely on other influences in your relationship to help you know it's time to pull back and perhaps offer an apology for hurting your sweetie's feelings. But in general, you'll push each other to do and achieve more than you would on your own, and that should be a very positive characteristic of this relationship. Working together on projects could be difficult if you let that competitive undertone turn into outright challenge and arguments; do watch yourselves when you have to function as a team.