Facebook and fiction: Characters meeting again after many years

Perhaps this is a result of the influence of Facebook but - has anyone else noticed - a # of stories of late include the device or plot element of a brief encounter in adulthood with an early flame - generally someone who caused great emotional or physical harm - and the late encounter generally proves to be unsatisfying, non-climactic: Didn't Tessa Hedley have this theme in a recent story? and Margaret Atwood? And it seems to me - though I may be wrong here - that Alice Munro has used this motif in a # of recent stories, including her most recent, Asmundsen (?), in the current New Yorker. This theme makes sense for Munro, a writer in the autumnal stages of her great career; most of her recent fiction - and many of her earlier stories, too - are notable in that they encompass an entire life span of a central character. The late-life encounter is a way for her, and apparently for other writers as well, to present a dramatic conflict of youth and then resolve the conflict or revisit it without building the story out to the length of a novella: the final encounter is generally a little coda, like a grace note at the end of a song or a closing image in a poem. Munro's current story, like so many of hers, takes place mostly in a small, rural Canadian town in the 1940s (war era) - young woman arrives from Toronto to work as a teacher in a sanatorium, and begins a relationship with the san's doctor. (Spoilers here): they head off to a nearby town to get married by a JP, and immediately before the ceremony the doc tells the woman he can't and won't go through with it - no explanation - and puts her on a train back to Toronto. Many years later they pass each other in the street, say a few casual words, and move on. I love many things about this story - but not the ending; I think Munro owes us more than these few words between the characters - some hint at their (or her) emotions and some clue as to who the doc is and why he broke off the relation so cruelly. Actually, we can see (evidently much more than the teacher, Vivian, can) that the doctor (Dr. Fox - interesting name) is a real self-centered bastard, enjoying his sexual prowess as the only man around (everyone else at war). That said, why would he lead her to brink of marriage and then break it off? There are some hints - perhaps Munro's reference to the letter "S" and to two boards crossed bracing a broken step - i.e., : S - X - is a pretty solid hint - but to what end? Is the doctor gay or repressed homosexual? Or is it that his only interest in the teacher is the sex - he feels (for a time) obligated to marry her (she was virgin when they'd met, and he's kind of old-fashioned in a creepy way), which he later shakes off? Anyway, no one's better than Munro at establishing the milieu of these lonely Canadian outposts many years ago, and of a young, often provincial, woman just beginning to make her way in the world, against many social conventions and low expectations.