Responses
for shoujo
in my opinion here this fits "not the obvious pers." (though you have more than 1 couple)
http://www.mangago.zone/read-manga/h2o/
http://www.mangago.zone/read-manga/yasashiku_oshiete/
You'll go from "oh god please, no" in the first chapter to "oh I see, I'll take that" afterwards...

I'm looking for a story can be either Yaoi or not where the main character(guy/girl) doesn't end up with the obvious person in the end. I want a good story and interesting characters not something, where the MC changes her/his mind in the last chapter or things like that. If anyone could suggest something like that, it will be great.