I’m confused what is wrong with them what is the issue here

As far as I can tell, Hayato realized he was gay in like high school and had a crush on Yuki but figured Yuki was straight. Rather than ruin their friendship he just gave up and started dating around. Yuki was actually gay and caught Hayato kissing someone so proceeded to be the friend who “happened” to always be around but really was just jealous and trying to block Hayato from sleeping with anyone else.