
You're right about the seme being a tsundere and has been interested in the omega since long time ago. But no, we don't know yet wether they both are really the fated pair since there's no confirmation yet. Then again, we could always fantasize and make up our own guesses, right? And I also think that they both are probably fated~ let's just see what's stored in the future chapters^^

But the seme does believe in pairs and I'm pretty sure he knows the uke is his fated pair he just tries to lie and play it off, like he does about not being attracted to omega pheromones. The seme gets drunk and complains about it at the new years party.
Evidence: http://www.mangago.zone/read-manga/hanagara_tsumi/mdx/mpn_chapter-1952856/pg-28/
So Tsundere Alpha seme who says he's immune to omega pheromones has always been in love with shy/slutty omega uke but can't tell him because he wants to make sure the uke likes him back, even though they are bonded by faith and possibly pregnant? Did I read all that correctly?