Love is a popular and reoccurring theme in fiction and is approached from several different angles. Is there a magical mathematical formula explaining how to make a smoking hot romance? Or is it a nebulous mess, thrusting all who consider it to madness. I think, both.
The only constant in love is two (or more) people who show higher than normal regard for each other. There are varying levels of love but not on something as simple as an axis. Love only starts in one place and ends up in another, but to map what is in between one needs a much more complex map.
One of the most interesting things about love is how differently it plays out given specific situations. I think the best way to express this point comes from the Multiverse theory. If you compared a couple to itself, tweaking the numbers so the relationship plays out in different ways. Under what conditions would the relationship fall apart? What trials would make the relationship stronger? What conditions would leave the two friends rather than lovers?
Some people start as close friends and eventually open the door to their heart into intimacy. Some people start intimate and realize through their carnal connection their lover is who they want to be with. Some people think they’re head over heels with the greatest person in the world, only to find the interest is gone once the lights go out. The dynamics surrounding the mystery of love is a gold mine for fiction.
Even if you take the L word out of the equation, the same principles form interesting conflicts. You can apply the same logic to any two characters to decide how they would interact. Where did they start? How do they end up? Even graphing a complex thing like love can be easy if you know the start and finish. You can check your logic by scaling out far enough to see the start and finish of your story and zooming in a bit closer to see the start and finish of a chapter. Once you apply the rigid facts to story, you realize exactly how much wiggle room you have for improvisation. If you know the subjects and you know the destination, writing the stuff in between can be not only easy, but fun.
The best part of writing fiction is you don’t need to follow the straight line. Even if you know how it should play out, doesn’t mean you’re obligated to follow strict logic. Love is far from logical. However as a creator of fantasy you are the logic and you only need to present it in a consistent way.
When I write about love, I keep it simple. I know the starting point, I know the possible destinations and I know the roads in between. Like any aspect of writing, it is all about the journey.