@LordTrollbias
I think it does have something to do with the fact that the Zedan and Astres already developed a mutual love together for so long, that it does come as more captivating.
They are the childhood friends that ended up together, married by the God of the Underworld himself, so yeah, they better be one hell of a power couple.
Meanwhile, Kidan and Platty are still in that "getting to know" phase of their relationship. They clearly do like each other and they care for each other, they just need some time to grow.
So in the end, yeah, it's not weird that Zedan and Astres are the more interesting couple.