I like this story, but I can't forgive cheating. Don't get me wrong. I want Mamoru and Hiroki to be together, but I want Mamoru to suffer a bit more (edited).
Great way to solve the situation! It would have been tragic no matter what, if it actually had been the same guy. I felt a bit betrayed in the beginning, since I believed that the seme had chosen the brother even though he had met the uke first.
Somehow it feels like every seme of this author is in some way or another a bit cruel.