From a young age Amy, Rory and Melody had been best of friends. Rory had participated in dress-up games of doctor and even on at least one occasion, when he played hide and seek with them, he hid for hours while Amy and Mels neglected to look for him.
Amelia was consistently the dominant member of her trio with Rory and Mels. Throughout primary and secondary school, Amelia unwittingly reared Mels, serving in loco parentis and lecturing her after each of her myriad discipline problems. Meanwhile, Rory went submissively along with Amelia's instructions and took her mild abuse, so long as it allowed him to be near her.
Because of Rory's timidity toward making any romantic overtures toward Amy, and his obvious disinterest in other girls, Amy incorrectly assumed him to be gay. In their late teens, Mels caused Amy to realise Rory's feelings toward her and she returned his affections. In doing so, Mels, being their daughter, paradoxically caused her own existence.
At some point, Amy and Rory started to have a relationship with each other. They were 'going out' with each other. When Amy met the Doctor again, she proved uncomfortable with admitting her relationship with Rory, at least to the Doctor.
Amy and Rory meeting the Doctor
Amy and Rory both met the Doctor in 2008. At this time, they were both going out with each other. Both Amy and Rory helped the Doctor defeat Prisoner Zero and warn the Atraxi never to return to Earth. The Doctor then disappeared to take the Tardis to the moon for some new engines, however arrived back two years after.
At some point before the Doctor's next return, Amy attended a fancy dress party with Rory. She wore her WPC uniform, whilst he dressed as a Roman centurion. She tucked a snapshot from the party into a book on Roman Britain.
Amy was engaged to be wed to Rory on 26 June 2010. On the night of 25 June, the Doctor returned to keep his fourteen-year-old promise. She joined him on condition she be returned before morning, but did not mention her wedding.