Board Thread:The Reference Desk/@comment-6036560-20140115001752/@comment-26975268-20140115003520

Nowhere in The Pandorica Opens/The Big Bang do Amy and Rory never exist, nor is there a timeline where they don't marry. It was the Doctor who was erased from existence in that two-parter, and even that was quite temporary. Rory was erased in Cold Blood, but we don't actually see River again anyway until Rory comes back. If you're referring to the entire universe getting erased, she was saved by the TARDIS, which put her in a time loop until the Doctor came to save her. Then she and the others were preserved as, as the Doctor explains, "the eye of the storm [...] We're just the last light to go out."

In any case, answering your question beyond what the stories say would necessitate speculation, which we don't allow in our forums (fora?).