Well, since made a post that went way off topic, and then decided to delete it, I figured I might as well make a post that's ON topic.
When it comes to attraction, I think there is a lot of validity to this. This is doubly true if you are an extrovert looking for a fellow extrovert, or an introvert looking for a fellow introvert. It provides an avenue of bonding. I think opposite pairings, where the inferior matches up, occurs when an extrovert is looking for an introvert, and vice versa.
To further muck up the theory, though, I wonder if gender would play a role in having the tertiary of the female better suited with the dominant of the male? This would make the male stronger in the area of bonding, which as controversial as the topic is, is something that BOTH partners tend to appreciate more often than not.