I'm looking for a yaoi manga in which the uke was getting married to the seme's sister. Th...

I wanna know too...

This? :O
http://www.mangago.zone/read-manga/yuushitessen_no_koi/

Thank you but no ;P I remembered more, and the wedding doesn't takes place because they get together.

Hmmmm....i didnt read that one, but maybe this? http://www.mangago.zone/read-manga/secret_diplomacy/

That's a good one! I've read that one...still ongoing though...

I feel bad rn no it's not x(

Damn it. xD Okay i will help you later again, because i'm already at work and cant come online till evening. Maybe someone will find it until then. Good luck!!~ <3

I will read it if it gets finished. :D

You should, it's good. I love all of Nitta Youka's work... Haru wo Date Ita is my favorite yaoi manga... and it's complete... although there is a sequel who is still ongoing (Haru O Date Ita Alive)... anyway, if you haven't read this mangaka, I highly recommmed it :-)