I'm trying to recall the name of a short story I read in an anthology (Best of the Year?) from the 1960s or '70s, in which a man taking a walk in a field meets a young woman who claims to have travelled there from the future.
She says the field is a department store in the future and that her father invented a time machine that she uses to visit the more picturesque past. "Yesterday I saw a deer, and today I saw you," she says at one point. The man thinks there's something familiar about her, but can't place it, and sees her for several days in a row.
One final day, she arrives in tears, saying this is her last visit, because the authorities have come to confiscate the machine, which is illegal. He never sees her again, but comes to realize that she used the machine one last time to go a little further into the past, and become his wife.