It's one week before the wedding and Arthur isn't nervous at all. But that's just the beginning.

This was originally posted at the kink meme here for this prompt:

Arthur/Merlin, Arthur/Other

Arthur and Other are in a long distance, unhappy relationship. For whatever reason, Arthur is expect to stay with Other. He meets Merlin and they strike up a fast, emotionally deep, friendship. They often flirt, and have some romantic feelings towards each other. But Arthur and Other have discussed "The Line" which would define cheating on each other: Kissing on the mouth, any touching of private parts and sex.

Merlin goes to visit Arthur for the weekend, at night the end up having a light make out session, but never cross The Line. (kissing/biting necks, playful wrestling, frottage, whatever) On the last night together after an intense session they end up with their mouths barely touching, whispering to each other, but still maintaining The Line. They both want it so badly but they know how guilty they would feel if they crossed The Line.

In which Merlin is the most harangued PA in Westminister, Arthur is on the back of the backbench, Uther harasses Merlin (though the Queen never does), Morgana is very clever, and the datebook will take its revenge.

Or, How in his tenth year of rule King Arthur chose a man to take the role of Court's Magician, and how Arthur made his decision.

Gwen answers what Arthur doesn't say instead of what Merlin does. "You'll be a good king."

“If she wants shoes she can come here and get them.”

Lancelot was not a great man, sprung as he was from common blood and barely proven. It was not for him to cut away that magic, steal for himself a little piece of a power that could render Albion mighty. It was neither right, nor his right.

"How long do you think it will be, before Uther learns the truth and both your lives are forfeit? Come with me and he will keep his life. By all the ancient gods I swear it."

He wonders if Arthur has exactly the same look for Gwen.

She wants to scream, to cry out at them to look at what it is they would be destroying. Arthur, her Arthur, is the greatest king that Albion has ever known. Beneath his benevolent hand the lands have known wealth and prosperity, they have unified and built up links of trade. Barely has the taint of war been known and the scars of previous generations have faded, hardly remembered. And now it comes to an end.

Yes, Merlin understood Morgana. Because he knew all too well that before long he’d be following a similar path, and telling Arthur – no matter how tempting – was something he couldn’t afford to contemplate. It was for Arthur’s sake, and Merlin could not stand to be ordered to stay.

Finally decided to get up, did we. Still lazy as ever, I see, your Majesty."

Then that particular group of girls who always sit together—and out of all there's only one he thinks is hot but she never looks up at the right time—sitting next to Heineken, a broody kid who takes his skateboard to class, and whose real name is forever lost due to a supposed incident during first year introduction that involved a beer bottle, an unsavoury way of putting it to use and a partner too drunk to care.

The first time Merlin had burst into flames (and Arthur made a note to remind Merlin, the next time Merlin complained about a 'life of forbearance and servitude to a man who makes no allowances for his advisors, and is in fact so unyielding, so sulkingly unyielding, that he will not even wear the thicker-soled boots with the yellow stain on the heel unless it is the second hunting Tuesday of the month, even when it is clearly raining outside', that Arthur’s thoughts regularly featured statements such as 'the first time Merlin had burst into flames')—the first time Merlin had burst into flames, absolutely without warning, Arthur had not managed even the moment of calm he was desperately grasping at now.

One time they get re-born as brothers.

Arthur grits his teeth and feels Lancelot's hands on his back. "I didn't save one to lose another!"

Gwen and Lancelot cannot be allowed to get away with their betrayal of Arthur.

Merlin was never an old man when Arthur was crowned, just an old soul.

This is the punishment Arthur devised for him, he realizes; betrayal and disloyalty repaid with unforgiving, implacable forgetfulness.

"No! Arthur. You're straight, all right? You're completely and entirely straight. Because if you're anything else, if you're gay or bi or even curious or what the fuck ever, Arthur, you will ruin my entire fucking life."

Getting married wasn't supposed to change anything.

"Here," said Sir Godfrey, who was the worst of the lot, "I shall draw some diagrams for you. You there, fetch me a quill, boy."

And Merlin, Court Sorcerer, who was probably enjoying himself too much at Arthur's expense to be bothered about being addressed as "you there", fetched.