It's an old saying that opposites attract and it's true that you often see two people together who seem very different, but are happy with that. It may be that we are fascinated by whatever seems different from ourselves. However, some psychologists believe that often, we see a quality in a person that we find attractive because it is 'different' but in fact this quality is one we have suppressed in oursleves, rather than one we don't have. So a person who has never dared to show anger may be attracted to a very openly angry person; or a shy person can be attracted to the loud, partygoing extrovert because that is who, deep down, they would like to be themselves.

So even when opposites do seem to attract, there may be more to this than meets the eye. In general, anyway, it seems that people are more attracted to partners who are like themselves than otherwise; but of course this is only in very general terms and doesn't always apply.