You either complement each other well or antagonize each other for your differences -- and the latter is the more likely of the two possibilities, at least until you can learn to get along. In the beginning, when the relationship was new and immature, you probably worked well together; your lover supplied energy and excitement and you acted as a grounding influence. They were able to encourage you to be more spontaneous and carefree, looser in making plans and so on, while you had good lessons to teach them about responsibility, planning and hard work.
Problems now arise when your partner's passion starts to get dampened by too much focus on responsibility. Your sexual connection could be doused like a flame under water if your energies are mismatched too often, or when you find that you want some very different things in the bedroom. You're actually likely to be made uncomfortable by your lover's carefree, adventurous spirit. It could make you feel nervous and unstable to be faced with such an unpredictable appetite, and your natural response might be to try to exert control over it and hold it down. But that doesn't work for long, and it only creates rebellion and even more unpredictability within your partner. Instead, why not try to get to know each other as the people that you truly are, even if it scares you (or bores you)? You'll probably find that your differences aren't so frightening or annoying after all, and in fact, they could be complementary, if you both give each other plenty of space.