i like it but why all the josei stories are the same.

Not all josei stories are the same. But all harlequin stories are pretty much the same.
(This manga, as well as other jousei, is a a manga adaptation of a Harlequin "novel/novelette")
If you want to read different josei, find some original josei manga.
Maybe you can try some of my favourite jousei manga/mangakas:

By author:
http://www.mangago.zone/r/l_search/?name=OHMI%20Tomu
http://www.mangago.zone/r/l_search/?name=Enjouji%20Maki
http://www.mangago.zone/r/l_search/?name=Yoshihara%20Yuki (this one makes hilarious stories)
http://www.mangago.zone/read-manga/soryanaize_darling/ (I've only read this one and Happy Rush from this mangaka but they were both good)
http://www.mangago.zone/r/l_search/?name=ooya%20kazumi (this mangaka also has yaoi, so you have to really choose the manga)

With anime/live action (that I know of):
One of my favourites http://www.mangago.zone/read-manga/gokusen/
Another favourite http://www.mangago.zone/read-manga/taiyou_no_uta/ (has live action drama and movie, I cried with both)
http://www.mangago.zone/read-manga/nana/ (really famous, but I never managed to finish the anime, but maybe because I was too young then)
http://www.mangago.zone/read-manga/paradise_kiss/ (another famous one by the same mangaka, watched the whole anime and the movie and liked it)
Another a really different one: http://www.mangago.zone/read-manga/amatsuki/ (it's tagged as jousei)
http://www.mangago.zone/read-manga/hotaru_no_hikari/
There's also Nodame Cantabile, but I've never read or watched it


Other josei manga:
http://www.mangago.zone/read-manga/kimi_wa_kirakira/ (somewhere in the line between shoujo and josei)
http://www.mangago.zone/read-manga/are_you_alice/ (still ongoing but very different and interesting)
http://www.mangago.zone/read-manga/annarasumanara/ this one was quite interesting
Another a really different one: http://www.mangago.zone/read-manga/amatsuki/ (it's tagged as jousei)
http://www.mangago.zone/read-manga/love_stalking/
http://www.mangago.zone/read-manga/sengoku_blood/
http://www.mangago.zone/read-manga/obito_no_hime_to_kubinashi_kishi/

... And the list has already become quite long, so I'll stop here. ヾ(❀╹◡╹)ﾉ~

thanks