Since you didn't say they have to be the main couple, I'll add one of my favourites:
* "Sex pistols" (Yonekuni x Shiro)
(You can watch the OVA because their are the main there)
* "Ai no Kusabi" and "Genwaku no Kodou" are from the same author and the main(?) couple is Blond Top x Black haired Bottom
* Some of the author Yamane Ayano
* "Dos Obak......
Thank you @Jia for the updates! You are the best!! (/TДT)/
As for the bubble you had doubts about, I thought that "It's the job I'm against", or whatever that Reiji said, it's good enough because he seems to be against the idea of the week he has to be far from Akito, like "If the work is going to keep being like this, I wish I could take him with me" or "i don't want to be apart form him for so long". Then, with the others saying he didn't use to complain with work journeys he counters(?) saying "I'm not against travelling for work, I'm against the idea of going for so long without my wife/husband/married partner... basically, my Akito"