You can tRyan reading hapi mari
hahaha, your question reminded me exactly of this manga. It pretty much fits your description but it gets fairly complicated. It starts slow at first so give it some time.
Goong:
http://www.mangago.me/read-manga/goong/
in shoujo you usually had the engagement stories or sempai stories instead of marriage of convenience. umm i'm more of a josei fan, and there's seriously a lot of stories involving that theme in josei. this is one of the best in that theme, i think http://www.mangago.me/read-manga/anata_ni_hana_o_sasagemashou/ she did want to get out of the engagement but there's initially no other party.
Thank you all
Does anybody know about shoujo manga were the couple have to marry each other and at first hate each other then fall in love or that they are to get marry but they love some else and fight to stay with that other person ٩(๑❛ᴗ❛๑)۶
Thank you (๑•ㅂ•)و✧