If ever you've wondered why dating people so much different from you doesn't seem to work out in the long run, here's your answer. It turns out Paula Abdul was wrong: opposites don't attract.
A recent analysis of eHarmony's Compatibility Matching System revealed that, as you might expect, similarity may just be the key to long-term relationships. Opposites, contrary to the pop culture belief we've been instilled with, usually fizzle out after a short period of attraction.
Which, of course, makes sense. Difference—something out of the ordinary—is a huge draw, especially in terms of a romantic relationship. It's exciting and, well, different. This explains the dominant/submissive paradigm we've seen in relationships for years, but the lack of real-life couples like Malcolm in the Middle's Hal and Lois seems to inform the eHarmony conclusion a little more.
According to researchers, the initial period of attraction "opposite" couples experience usually gives way to an "attack" period in ways that like couples aren't likely to endure. Primarily, that's due to the ability those couples have to clash as equals rather than on a dominant/submissive paradigm.
So, if on your next date you find yourself thinking, "Hmm, one of these things is not like the other," head for the door. At least until the next study comes out saying otherwise.