Most couples can name several ways in which they're opposites: neatness versus sloppiness; extroversion versus introversion; being high-strung versus laid-back preferring city versus country living, etc. And I'm sure you have something in mind that's specific to you. It's true that quite often and in many respects, opposites attract. But those areas can either help you thrive as a couple or destroy you!
Look at it this way: To the extent that you see or prefer things in an opposite way, you always have a choice. You can allow those ways you're opposite to destroy you or be a constant and endless source of trouble for you by demanding that your partner be just like you; or you can help them to morph into some of your greatest strengths. The key to the latter is to recognize that your differences can give you a much greater range and perspective as a team than you could ever have on your own
The choice is yours. Couples, who use those opposite characteristics optimally, operate with four eyes and four ears, rather than negating and making each other wrong -- which will create a perpetual and perhaps unresolvable conflict.
Here's an exercise to help you look at the items where you are opposites in your relationship: Have a lighthearted (as opposed to hostile) discussion about all of the ways in which you recognize yourselves as being opposite. Make a list of all those opposite traits or preferences that you are able to recognize. Then, review your list, assigning a plus (+) or a minus (-) next to each item you've identified to indicate whether your opposite trait is a positive or negative factor in your relationship. Couples who take the time to do this thoroughly are usually quite surprised to find that most of their opposite traits actually serve them! (Obvious examples: One loves to cook; the other hates to but loves to eat; one is a good money manager, the other is inept at handling finances; one is a very strict parent, the other is quite liberal.)
For example, one couple I worked with demonstrated a common example. His idea of a vacation is to go someplace warm, and lie on the beach or at a pool. She loves vacations where there is lots to do and see. In fact the more her schedule is crammed with activities when she is away, the better. They fought so bitterly about their vacations that they spent several years not going away at all, despite the fact that they could well afford to. Their solution: vacations where each could do what he or she wanted. Sheila found a few handpicked activities John would enjoy, so he wanted to join her. John could spend the vast majority of his time during the day doing what he wanted -- while Sheila was partaking of the rest of the sights. They both believe that this simple effort changed the entire climate of their relationship for the better, by defusing a chronic issue.
Now take a look at each item that you have identified as negative and discuss a strategy to use that opposite trait to your advantage.
No matter how opposite you may be, chances are there's common ground. Your challenge is to find it, rather than making your partner wrong. Consider that common ground as the strength that can help you to convert those parallel tracks to ones that are convergent! Couples who commit to doing this are usually delighted to find that they do make a great team -- even though it may never before have been apparent -- simply because they learned to complement one another.