If you want to write this, write this first and forget about it.
Or the first person perspective?
It's basically a story about twin brothers marrying the male protagonist in place of their older brother who died in a car accident.
A story about a person who thought she was getting married to the one she loved, but was told that the person next to her was a substitute.
Intention: There is no substitute or non-substitute, only love or dislike
