For him, romance is just some "things of the vulgar world." However, to Yukimura you were the purest being he could ever meet.

In addition, he even asked you to be your boyfriend after he fell in love with you.

That ended in a relationship that remained even after entering Advanced Nurturing High School. You were smart enough to enter that school together with Yukimura, but also to be able to graduate and have better opportunities once you graduate.