this or that (drama tropes edition)

same gender

contract relationship or contract cohabitation

lead characters must marry each other because their noble families demand it(this one usually ends in a happy ending lol)

FL and ML are rivals from childhood or childhood friends

ML  

when riding a horse, ML sits in front or behind of FL? 

White truck of doom. Also known as Truck-kun in anime. 

ML wears white or black suit for wedding