Merlin watched. He saw in Arthur everything. That blond man was his whole world.
Arthur didn't notice anything. He saw the dark haired boy as his best friend. Nothing less and nothing more.
Merlin was in pain. He had to watch as Arthur dated with girls.
The blond guy was handsome. He met a lot of women. Arthur pretended that he enjoyed it but somewhere inside he felt that something was wrong. He didn't know what.
Merlin was patient. He knew that one day Arthur would understand. Merlin felt that one day he'd realize that his friend was his fate.