The Dandelion Girl.

Based on the short story by Robert F. Young. Written in 1961. Mark, a middle-aged man encounters a young, mysterious woman, while staying at his cabin, who claims to be a time traveler from the future. Over the course of a few days, Mark and the young woman, Julie, begin to form a budding romance with one another. Mark is unhappy in his life, in a stale marriage, where he goes through the motions of living and work.