Quote Originally Posted by Tallmo View Post
From a DCNH perspective:

It doesn't matter what the relationship is. Subtype match is always the same. So also for duality it has to be either D+N or C+H.

If you really are a Creative then you need a Harmonizer regardless of the socionics relationships. But I also see some D+C so that might function sometimes.

If you use 2 subtypes there is a risk that you are not gonna get the desired precision for a realistic match.

I have dated duals of the "wrong" subtypes and there is clearly some basic flaw in such a relationship. DCNH is imo the basis of any stable relationship.
Some relatives of mine are an IEE-Fi - LSI-Se couple. He is is D, and she is N. They're a very unhappy marriage. I think the original inter-type matters more than DCNH, but you are spot on on that most couples are complementary DCNH pairs.