It doesn’t have to be a lover. It could be a friend. A child. A motivation. An enemy. An opposing point of view, given voice by a character.
That special someone creates an impact on the protagonist’s life. Bringing chaos, conflict, questions, and/or action.
That someone gets the main character to do something, gets the plot moving.
No, it doesn’t always have to be a someone. It could be a something. I, however, have always been drawn to character conflict.
One of the first things I write in a story is the dialogue. Conflict initiated through conversation. A plot beginning with the interaction of two characters.
How about you, dear reader? Does your protagonist have a special someone? How does that move your plot forward?