So..now I'm searching for Manga where Uke is gay fro start and falls in love with straight guy..hopefully no One-shots ..It can be Dark[I dob't know why but I'm obsessed with it] or Cute/fluffy[with cute Art]

I don't know if you've already read them but give a try to Ashita mo Tanin and Mirai no Kioku 😃

Hopefully some of these fits what you are looking for. It has been a while since I have read some of these so I am just going off of memory....

I Want to Become Your Bird
Cafe Latte Rhapsody
Ai wa Doko Itta?
Akanai Tobira
Ano Hi no Kimi wo Dakishimeta nara
Cut - I don't remember if the Seme was straight or not, but I know that he was a virgin... well I think .><
Boku no Shiru Anata no Hanashi
Dekiai Rule - Don't remember for sure is Seme was straight sorry 😢
Fake na Junjou
Honto Yajuu
Kimi ga Iru Basho
Kimi no Kao ni Sasu Kage

Hopefully a couple of these will be what you are looking for ^.^

Sheory and xXGazeChicXx thank you very much...I have read most of it but there are some's I haven't so will try redaing it ^^

p.s still waiting for more

p.s.s again sorry for my english -_-

I am glad that some of the ones listed were some that you haven't read before! I looked through the rest of my list and I found a few more that may fit in with what you are looking for.,,

Konbini-kun.
Kuchibiru no Yukue - I don't remember this one very well, but I think it has to do with a uke falling in love with a straight man. Either way I do remember that it was a good read ^.^
Megane Goshi no Sora wa... - This one kinda fits
Mujihi na Otoko - and it's sequels (all of the stories related to this manga are really good, but this is the only couple that fits your description of what you are looking for)
My Life with You
Usotsuki wa Dareda
Yuuwaku no Kaori

Maybe there are a couple of these that you haven't read yet 🙂

`Thanks <3 there are some I have read bit are some I haven't read too... 🙂