If you've ever felt like you get more out of your workout while exercising with a partner, it's not just your imagination.According to a study published in the Annals of Behavioral Medicine, working out with a partner can, in fact, increase your performance. The results of the study probably aren't too surprising. After all, not only can working out with a partner help when you need a spotter at the gym, exercising with someone else means you can keep each other motivated. Not to mention, it can make it more fun — especially with a significant other.In fact, another study from researchers at Indiana University found that married adults were far more productive and motivated when they attended fitness classes with their partner than those who attended classes alone.And while there's nothing wrong with the classic dinner-and-a-movie date — it can get a little old sometimes. Trying new and exciting things together can be great for your relationship. New experiences, according to research from the State University of New York at Stony Brook , trigger the same brain chemicals that are ignited during your relationship's early romantic honeymoon phase.