I don't know about that... We've been together 16 years, and still in love. But we are different, in ways that sometimes he does not understand my reasons, and there is no way I can accept some of his, but somehow we complement each other. Our diversity ends when it comes to core values, we have those very much in common.
So I guess you can see that as soul-matism (I know, that's not a word). In our case it's about being complementary on the style, but similar on the core, if that makes sense.