Banned, taboo, off limits, not allowed, verboten. Forbidden.
Since the beginning of time, the prohibited fruit has always been the sweetest, the most tempting. Thousands of years of human existence, but we don't learn. History repeats itself again and again, each generation echoing the same mistakes as its forbearers. She is the Eve, and he is her apple, if one cares to look at it that way. She doesn't believe in that story, but the irony astounds her, makes her smile sardonically.
As their passion increases, as he enters her, as she silently cries out in voiceless ecstasy, the back of her mind persists in wondering what should happen if they are caught. He seems not to notice, but later, when she thinks he is drowsing before they must part so as not to get caught, he rolls over and eyes her half-critically, half-sadly. He kisses her face gently, asking her in a murmur what is wrong. She answers simply that she does not want to lose him. He understands, for he worries about the same things, though he, like she will not say it. He is the Romeo, and she is his Juliet.
And when they part, it is without a promise of seeing each other again soon, for such promises are too easily broken. There are no guarantees in this life of secrecy, no way to be sure of anything. All they have to sustain themselves through the long days and longer nights is a vague notion of that far-off "someday" when things will change, when they will be free to be together. Someday.