Yaoi mangas where the seme was first straight then it starts to fall in love with the uke

following

http://www.mangago.zone/home/mangalist/135746/
Idk this might help

http://www.mangago.zone/tag/straight%20seme/
This too

I have a very detailed list that largeky involves sexuality just go straight to the straight x gay section and pick out the straight seme
http://www.mangago.zone/home/mangalist/43415/

The seme in this manga is super hot and he's bisexual:
http://www.mangago.zone/read-manga/kyouju_to_shitsuji_no_shizuka_na_seikatsu/

Straight seme charmed by cute uke:
http://www.mangago.zone/read-manga/houtou_musuko_to_sewagakari/

Straight uke falls for Hot seme:
http://www.mangago.zone/read-manga/24_jikan_eigyouchuu/

Gorgeous straight seme and cute uke:
http://www.mangago.zone/read-manga/renai_fuyuki_todoki/

Same like no.4
http://www.mangago.zone/read-manga/heart_no_kakurega/

Stoic straight guy charmed by gay Gyaruo uke:
http://www.mangago.zone/read-manga/neon_sign_amber/

Enjoy!!