Black & White, for something completely different.
Or any of NANANAN Kiriko's Josei works.

The story Emma should be up your alley. I haven't actually read it yet, but some of my friends have and it seems to fit the bill.

http://www.mangaupdates.com/series.html?id=104

Summary: In Victorian-era England, a young girl is rescued from a life of destitution and raised to become a proper British maid. Emma meets William, the eldest son of a wealthy family, and immediately falls in love with him. William shares her feelings, but the strict rules of their society prevent their relationship from ever coming out in the open. Traditional class distinctions and rich, historical details provide the backdrop for this appealing romance.

paradise kiss' yukari fighting <3 😎

I suggest reading Paradise kiss and Ao Haru Ride. These two are among my top romance animes with mature themes but still make you feel giddy and in love. They also tackle a few life challenges which makes the plot even better