Sweet or Bitter Love (manga)

I don't think that our love might be reciprocated. I'm happy with a lifelong fruitless one-sided love. --Or so I thought, but then Odajima showed up at the matchmaking venue...!? And for some reason, he seems to be positively considering marrying me.

Wait! Aren't we living in different worlds?! Because I'm gloomy and servile, and you're cool, kind, and popular...? And so we're... getting married!?!? A see-saw game of obsessive love between a super-obsessive top and an unconsciously loved and servile bottom!