Maybe you can even go as far as to create a story in which the two people are more than just casual acquaintances at the beginning.
If the game is a simulation, and the Official Couple continues their relationship, then your game could emphasize time management and making friends.
Likewise, many commercial games have a Slice of Life setting.
If your setting is realistic, then make sure you can portray it in a way that the audience will find interesting.
Do not talk about your awesome plans until your project is almost finished.
You can create a love story in which a single sex scene is an important landmark for the characters.