I had the idea in which Merlin has a ex-boyfriend, but no one knows until Arthur and the knights get to bring Merlin -finally- to a tavern.
They all knew that Merlin excuse of been in a tavern was a lie, Gwaine had never see him at any of the taverns in Camelot before, so they are determined to bring Merlin and tease him until he tells them the true. They get Merlin to go to the tavern with them under the excuse of celebrating the creation of the round table or something, an once Merlin is drunk, in way too little sips for someone who claims spending their whole free time drinking, the knights and Arthur start bombarding him with in questions.
Merlin, who is too focus on not spilling the beans about his magic, but too drunk to keep his mouth closed ends accidentally confessing, in kind of a subtle way, having a boyfriend - or something close to a boyfriend - once. He talks between sips and a melancholy tone about having someone who he trusted and cared about, but that in the end they both knew it was nothing but impossible to be together in the long run, no when the law and society was so against a relationship like theirs, it was not meant to be anything more than some moments take out of a dream and a memory to find comfort on. Then Merlin gets knock-out for the alcohol, at the next day Merlin doesn't remember a thing.
Now Arthur and the knights, feeling guilty since what it has start as a joke and curiosity had bring up something that Merlin actually carries close to the chest, something that wasn't theirs to uncover. They just didn't expect such a show of vulnerability and confession, and now they have to carry the knowledge of it, and thw worst thing is that Merlin doesn't remember and they don't know how to bring the topic up.
The knights and Arthur take in their hands the duty of (1) making sure that Merlin knows they love him and that he is their friend not matter what, (2) making some new laws that permit same gender relationships -Arthur and Leon are the ones more involved with this, but the other knights cheer them up- and last but not least important (3) try to guess who this ex-boyfriend, principally out of curiosity, but also with the hopes of maybe getting him and Merlin together again once the laws in Camelot allow it.
This could lead to many interactions:
Percival, not knowing how to tell Merlin that he knows, doing a cake and leaving it in Merlin's room in a effort to show his support and care that says "I know what you are" which lead Merlin thinking that someone in the castle knows he is a warlock and is trying to posion him.
Gwaine and Lancelot looking at each other suspicious since they suspect the other one is the mysterious ex, the other knights and Arthur also suspect, but they don't say a thing.
Gwaine trying to be Merlin wingman and said that "Merlin is gay and single", but without having to say "gay and single", there are a bunch of wink wink that confuse Merlin a lot.
Lancelot feeling hurt because Merlin trusted him about his magic but not about been gay, and waiting Merlin to be the first in mention it.
Leon looking to invite Merling to read poetry that he had wrote trying to make him understand through his poems that he knows, but also just wanting to bond through poetry.
Elyan giving a lot of pats in Merlin back and shoulders because he really doesn't know what to do to show his affection. He is also having a hard time not telling Gwen about Merlin been gay, because for one side, he himself wouldn't have know if he hadn't play dirty, but for the other one keeping this from his sister, who he knows cares about Merling is extremely hard.
Arthur has a crisis as he lays in his bed thinking if his best friend had keep this secret from him because he thought that Arthur would dismiss him. The worst thing is that he hadn't give Merlin a good reason to trust him with such a confession, no with all the jokes that he made at Merlin's expense about been too feminine or delicate, even when he knows that Merlin had grow to have a muscular body in his years serving him though to all the fights and murder attempts that they have survive together.
Arthur and the knights are also trying to guess Merlin type, eveyone had a type, and now that they know why Merlin never was part of the conversation once women were mention, they can't avoid trying to look at differente men and trying to decipher if Merlin would find them attractive or not, after all, if they do not find the ex, the would have to find Merlin a new boyfriend, gods know the fella deserves someone in his side that would love him unconditionally, but what starts as a research, ends in Arthur and the knights just looking at men for hours, unable to do anything else.
Also in my mind I have three options for who the mysterious ex can be:
George. If is more commedy than anything else I would choose George, just because I don't think Arthur or the knights would have ever think about him and also because we know so little of George that we can do anything we want with him always that we keep the fact that he is an amazing servant. Maybe he is actually a great guy, maybe Merlin and him are close, who knows.
An original character that is never found and is keep as someone that would only live in Merlin's memory, maybe someone he knew in his way to Camelot that follow his own way to another kingdom.
William, my personal favorite, because his sacrifice and death under this light could be interpreted as a show of his deep love for Merlin, it would also add to the whole sadness of the situation and could even lead Arthur to start thinking better of the sorcerers, because if his best friend was able to love and be loved by one so deeply, then not everything about them can be so wrong




















