There's an argument for that, but this isn't quite that, either.
They're good friends. Kim Wook (blue haired guy) has feelings for Yeo Reum (orange hair). They're one sided. He DOES try to confess, but it doesn't work out. Always something in the way. He constantly sees her being interested in other guys, like a senior whose name I forget. He shows his interest and care through his actions all throughout Season 1, it's pretty obvious, but the key thing here is he doesn't get a verbal confession out.
Later, in Season 2 after all this distancing, she realizes her feelings for Kim Wook and tearfully confesses how she feels about him. They reconcile and are an official couple by the end of S2.
So they know each other. She was too busy to notice him, and he was too passive.
And it is absolutely not being a dick to protect your peace and distance yourself from people. No one owes you anything, let alone an explanation, for why they ditch you. Likewise, you don't owe them anything either. If Kim Wook was hurt by all the things that happened (he was) then it is reasonable that he would walk away.
If she only realizes her feelings for him AFTER that? It's not just that he's passive (though showing love through acts) but because she couldn't see the forest for the trees.