Read Tinkerer before you read this~!

 Basically, Yunho and Yuri were forced into an arranged marriage because their fathers are business partners. They were expendable, so Yuri's father gave her away because Yunho's dad needed someone to marry his son. Yunho was unwanted because he had asperger syndrome, a form of autism that makes the person socially awkward and he would embarass their social parents. It's shown by the way his fingers tapped, or how he could never quite meet her eyes, as people with AS characteristically avoid eye contact or have repetitive movements. Yuri experienced some love in the form of her mother, so she is ultimately the stronger (emotionally) of the two. 

 Yunho's dad needed an heir, so he was angry when Yunho told him that he hasn't had any children with Yuri yet. The point of the whole one-shot is that no matter how different people are, they will always be the same regardless of their backgrounds/disabilities.

The rest is pretty easy to follow.  ^ ^

I hope that cleared up the storyline. I write in a strange way, so here's something to help you with.  ^ ^