Romance is indeed a flame.
Like a match, when first struck it flares, all consuming, turning that first bit of friction to a explosive flame. It burns bright, holding your attention, before it steadies itself and settles into a consistent burn. As it runs its course it doesn't vary, you can predict it every time which direction it will travel.
There are of course, variables. It only has a limited amount of fuel. If you neglect your attention to the flame, it will have deplete its supply, and smolder itself out.
If you hold it too close, you will be burned.
The wind, beyond your control, can rob you of its warmth.
If held too close to another match, the flame will jump, igniting another as yours burns out.
Each time, after the flame is gone, you are left missing its heat, the sensation fading on your skin. You are left wanting more, desperately trying to reignite a burned match left brittle after the burn.
The smell tickles your nose, stinging it slightly with its distinct aroma. This is the real ghost left in its wake. Each time the fragrance enters your mind, your memory thinks of the warmth, the spark that started it all and the flare as the flame burst into existence.
The flame is intangible, abstract to all else you have experienced before and since, yet it is there, and even if you can't touch it, you wish to capture it. All your efforts to do so result in smoke, as the flame chokes. So instead you try to control it, giving it ample food, ensuring the window is closed as to prevent a draft. You watch it as it grows and then you blink and it engulfs, engorges all before you, growing defiantly until you are burned alive.