your sister got into serious trouble with the dragon, she steal something from the dragon, and to return, she has to marry a dragon

your family love your sister much more than you, so they forced you to marry the dragon, replacing your sister

you married the dragon, the dragon can turn into a human form, but he always think he's a monster even in a human form. he always avoid you, he afraid you scared and he thinks you don't deserve a dragon like him

you never even talk to him