You, Who Hate Breaking Promises

[Campus romance, sweet first and angsty later] The hero and heroine are secretly in love with each other and choose each other against all odds. They go through countless hardships but still stay together. Then the hero's parents send him abroad. He asks the heroine to wait for him to come back so they can get married, but he ends up being gone for nine years. The heroine waits for him desperately, only to find him returning with a new woman by his side. She drinks herself into a stupor night after night and eventually, unable to bear it any longer, takes her own life. The second male lead, who had silently protected her all along, is so devastated that he can barely hold himself together. He chooses to die by suicide too, so he can be with her. When the hero hears that she has died, his heart is shattered and he nearly loses his mind. He loved her deeply. In the end, he has a pair of adorable twins, a boy and a girl, with the woman by his side, but she will never again see the beauty this world has to offer.