Proposal Flashback 

Yunho's POV

“What?”
“I want to marry your sister.” I repeated my words to Sunhee's dumbstruck younger brother, Oh Sehun.

I didn't want to nor did I have to but I wanted to tell Sehun my desires of wanting to marry his older sister. I thought it was best, seeing as how unreasonably protective he is, that I should inform Sehun of my thoughts before actually asking Sunhee.
“I heard you but what?” Sehun asked, emphasizing the last word.

I knew this would be the outcome. I knew Sehun was going to overreact and if it weren't for Sunhee's close relationship to her younger brother, I wouldn't give a about Sehun's opinion. (Not that I do anyway) And out of respect for my girlfriend, I wanted to give him a bit of a heads up but seeing his reaction now, I already had second thoughts.

“I don't know what you're asking for.” I replied, unsure of where he was asking for. Sehun his dry lips and ruffled his hair before fixing his sharp eyes on me, “Are you serious? Do you really want to marry my sister?”
I nodded in finality, “I've been together with Sunhee for six years now and I want to take the next step.” “Why?” He asked, his tone coming out a bit forceful. Sehun's pale, thin fingers reached for his cup of water that was placed on the coffee table. He grasped the cup into his hands and practically crushed the foam material. “Why do you want to marry my sister?”
What's up with asking the obvious here, blondie? “Because I love her.” I decided to answer instead of relaying my thoughts.
 

Sehun took a sip of his water, setting the crushed cup back down to where it was previously settled. “But why?” I clucked my tongue in annoyance and eyed the fidgeting boy closing, “You doing drugs?”
“No!” He exclaimed defensively and shot me a look with wide eyes, an expression so unlike his own. “Why would you even thing that?!”
“Then why do you keep asking useless questions?” I calmly, though coldly, snapped out the question.

Don't be confused, Sehun and I do get along but as Sunhee has said before, we were alike. Too much alike. While Sunhee and I were polar opposites that at times butted heads, Sehun and I were too much a like to not heads. It was during times like now, where Sehun's protective side over his sister came out, did we start to see differently.