Just a little one-shot right at the end of episode 8 when Arthur asks Merlin about his girl.

"Oh, so you can go visit that girl again?"

"What?" Merlin asked with a confused expression

"The girl." Arthur said again.

Merlin walked toward the counter and said, "I don't have one."

"That's not what Guinevere tells me."

A strange look passed between Gwen and Merlin, one filled with a sort of hate or resentment, but Arthur didn't notice.

"So why don't you tell us all about her," Arthur insisted.

Merlin put the pitcher on the table and sat down.

"Her name was Freya," Merlin said.

"So there is one!" Arthur smiled.

"No, there isn't." Merlin responded.

"Merlin, your not making sense," Arthur sighed.

"I used the past tense. My girl was Freya."

"What happened?" Arthur asked, genuinely curious, but also with a hint of amusement, "The two of you break up?"

"She was killed about five years ago. "

Complete and utter silence.

"What?" Arthur said, "Merlin I am so sorry. What happened? Why didn't you tell me?"

"She was killed by a man who thought she was the enemy. I didn't tell you because you wouldn't understand how I felt about her."

"I'm so sorry, Merlin," Arthur said again.

Merlin nodded his head in acknowledgement.

"But I'm still confused. Guinevere said you were visiting a girl and and your love is dead then…?"

Merlin hesitated before saying, "I was visiting her grave."

And this small act of kindness from Merlin, who had every right to hate Gwen for all she had done to him, brought her back from the dark side. She realized who her true friends were.