he has trauma, the love of his life got beaten up because of prejudice and he's just paranoid it's gonna happen again. for how they've stuck together with each other through thick and thin in this manhwa, i have faith they'll be together despite the problems...just hope he gets therapy coz dealing with trauma like that alone is not good
ngl I thought it was a wagging the tail spin off coz of the similar professor in the cover(╥﹏╥)