Gwen knew.
It was in the way Arthur kept Merlin by his side at all times. It was in the way Arthur pretended not to listen to Merlin's advice and warnings. It was in the way Arthur's iceberg blue eyes now sought Merlin's unwavering cobalt, not Uther's hard, glaucous eyes, for approval after every tourney or melee. Every action Arthur took in his duties to Camelot was subjected to the test of what his manservant would think.
She had always known how Merlin felt about Arthur. Merlin was an open book. The younger man's eyes followed Arthur, almost against Merlin's will. Merlin followed Arthur around Camelot, devotedly, like a puppy at Arthur's heals. He endured Arthur's insults and abuse steadfastly. Always there to make Arthur smile, to comfort him, to protect him, or to just be there with Arthur; a faithful presence Arthur could relax in.
Gwen had been a little surprised by how happy Merlin was for her, when it seemed Arthur wanted her, and a little taken aback by how eager he was to help them get together. Merlin's eyes still watched Arthur's every move and Merlin still got breathless whenever Arthur pulled Merlin against him.
Merlin would do anything for Arthur. Even, it seemed to Gwen, help Arthur get the girl.
But Gwen knew.
Gwen saw how Arthur's hands would become fists and how, despite Arthur's friendship and trust in Gwaine, Arthur's eyes would tightened whenever Gwaine touched Merlin.
Gwaine was very outgoing. He touched Merlin a lot. Gwaine was very… friendly.
Which was how Gwen ended up walking in on Merlin straddling Arthur, who was face down on the bed, moaning in pleasure. Gwen had sucked in a sharp breath and left as quickly as she had come. Later Merlin explained that it was just a massage because Arthur was so very tense. Merlin had been so concerned about what Gwen would think.
Gwen thought it was telling that Arthur never even mentioned it to her. He was too worried about the way Gwaine was manhandling his servant.
That was when Gwen asked Merlin and Gwaine to find Lancelot for her. They told her they would. Merlin looked ill. Gwen thought he was probably worrying about what this would do to Arthur.
Gwen then went to Arthur.
"Gwen!" Arthur exclaimed when she entered, "Have you seen Merlin? I suppose he's off gallivanting around the taverns of the lower town with Gwaine." The prince ended in a scowl.
"I asked the two of them to do something for me, sire." Gwen informed him.
"Oh, well, he should have told me first. I didn't know where he was…" Arthur trailed off looking slightly uncomfortable. Gwen held her tongue. "I like to know where Merlin is." The prince admitted.
Gwen couldn't help the smile, "I know." She told him. Arthur looked up at her, confused. "I know." She repeated, " I know you allow Merlin's cheek because he's really more you friend than your manservant. I know that despite how much you love your father, it's Merlin's expectations you judge yourself by. I know that you try to be touching him nearly every moment that you are awake, because the two of you are drawn to each other like the sand and the sea. I know that no one else can make you smile the way he dose and that when ever you are in one of your moods-"
"I don't have moods!" Arthur protested.
"The whole castle looks to Merlin because we all know that only he can pull you back out," Gwen continued, ignoring the indignant prince. "I know he knows you better than anyone-maybe even yourself. And I know that despite how you act, you are not oblivious enough to have missed seeing Merlin's magic." Arthur's jaw dropped. Something like fear crossed his face and was gone.
"How-" Arthur began, his voice hard with shock and worry.
Gwen smiled at the man she had once dreamed of marrying. The man she knew would be a great king. "Does it really matter? I know. You know. Neither of us let Merlin or the king know."
Gwen paused, she watched as Arthur's body relaxed, knowing Gwen would keep Merlin's dangerous secret. Arthur sighed and gave Gwen a rueful smile, "I keep waiting for him to tell me."
"As I now wait for you to tell me." Gwen informed the honey-gold haired prince. Arthur looked confused and slightly petulant.
"I know." was all Gwen said.
Arthur's shoulders dropped and the air went out of him, "Does he?"
Gwen shook her head, "He has no idea."
"I'm so sorry, Gwen." Arthur's face was tragic, but relieved.
"I know."