I never understood why it was in that genre, usually that genre is one girl surrounded by guys who want to be with her. In Fruits Basket, really only one guys loves Tohru like that.
No same applies to the anime. Many episodes mentioned Yuki having a crush on Tohru. Hatsuharu did in fact flirt with Tohru a bit and mention sex with Tohru when fighting with Kyo. Hatori formed a crush on Tohru because she reminds him of his wife he once had.