AN: I watched New Who completely, and then went and started with the First Doctor... and nearly died of laughter when he accidentally became engaged to an Aztec woman in the story "The Aztecs". Some things really don't change during incarnations.
Disclaimer: Doctor Who is property of BBC, and I made no money off of this fic.
It all began with cocoa.
It wasn't even supposed to be anything else; Cameca had approached him with the cocoa, and the Doctor, not understanding the implications, had happily accepted her offer. She was a sweet woman, gentle, and polite to him. She also was around his age appearance-wise.
Of course, if he had only paid some attention when studying Earth history, he would have known that sharing cocoa together meant engagement in 15th Century Aztec culture.
His enthusiasm for the cocoa had only encouraged her, and by the time he realized it, it was too late to back out of it - he, a Time Lord from Gallifrey, was engaged to a woman from 15th Century Mexico on Earth, and to back out of it now would probably get him executed by the Aztecs.
After the initial shock had worn off, he hadn't minded too much spending time with her; she did deserve better than how women were treated in those days. Poor Susan had received schooling from the Aztecs as to how to be a proper wife. Ian had seemed quite amused, but the Doctor knew Ian had been dealing with his own problems then.
Cameca had helped the four of them escape and had professed her wish to stay by him forever. Oh, he wouldn't have minded that, at all, if she had come with him. But he knew that eventually there would be immense culture shock, worse than the culture shock with Barbara and Ian; all the strange things they would see would frighten and terrify her.
One day, he could have to face the Time Lords, who wouldn't look kindly upon him marrying a woman from another species. They had always been a stuffy old lot, and what they would do to him didn't compare to what they could do to her. No, for Cameca's own safety, she had to stay behind and live out the rest of her life in peace, away from the danger. Traveling in a blue box in space was not for her.
Cameca wasn't his first love; he had had a wife on Gallifrey. She wouldn't be his last love, either; there were other people that he would find a fascination with, would accidentally become engaged, or even married, to. But Cameca would always hold a title that no one else could.
She was his first human love.
And at that point, the Doctor vowed never to share cocoa with anyone else ever again unless he meant to propose to them at some point.