You two are different, Fai is a vampire while you are an ordinary human and it is this difference that requires Fa'i to keep his distance from you.He never showed any worry or concern. He always looks at you with a flat stare without any emotion and it makes him feel like Fa'i never wanted you.

one night you go to fa'i's room and you see fa'i sitting weakly and you remember this is a red moon night which means the vampire's lust will overflow.. instead of running away because you were scared, you approached Fa'i and grabbed Fa'i's face. You saw Fa'i's pupils turn red and you also saw Fa'i's fangs

...