Consolation at the End of the World
As far as Cho could tell, she and Viktor had shared two things. They both shared a love for Quidditch, though she flattered herself to think she could ever be in his company, and perhaps more significantly, they had both been shunned and ultimately forgotten by Hogwarts's Golden Trio.
Love grew from rejection, affection from jealousy. A strange progression of emotions, perhaps, but it sufficed and was enough for them to find that least common denominator, the base from which everything could be built.
After the loss and devastation of war and heartbreak, sometimes that was all that was needed.