sounds a little bit similar to http://www.mangago.me/read-manga/mazu_wa_ubaiai/ but at the same time different, so i'm sure sure
i hope that this helps but try to go over my switch and role reversal list if the pic or title would remind you which http://www.mangago.me/home/mangalist/33677/
they did not. the uke has always been straight, it's the seme that has a gay unrequited love for him. it's just that the uke feels emasculated from being a bottom and other various reasons... because he's unsexy and manly like that. i just couldn't remember that part you mentioned haha, i kinda felt pissy with myself cuz this is one of my favourite manga.
I'm looking for a yaoi manga that had a storyline dealing with the seme telling the uke that he ( the uke) didn't love him in the same way because he never wanted to top. The uke struggled with his feelings and in the end it was a happy ending. That's all I can remember about the story. Does anyone know or think they may know the manga? I certainly read it on this site.