This is not a particularly famous or widely-published story, but it may have been anthologized once in one of the popular "Year's Best"-type antho's (or "Best of "If", etc.) -- probably where I read it years ago.
It's a tongue-in-cheek, dryly satirical story, probably pretty short, playing on the clichéd "Teenagers Save the World from Alien Invasion" trope. Here it is years later, All-American (former teenagers) Chip* and Molly* [*I'm making up the names, I DON'T remember them] are now married. They helped save the Earth from some diabolical alien invasion years before, but now life is mundane and lacks the fabulous heroic excitement of their thrilling moment in the sun years earlier. The story basically plays on how reality has set in (marital malaise, job tedium, no one wants to hear them (him?) reminisce Yet Again about "the good old days" when "[remember how] "we saved the Earth from the Aliens!"). I don't remember the ending, but it's basically a wry portrait of the clichéd fresh-faced 1950's kids from various stories/movies, only years on. Anyone know this story? Thanks in advance. (Was delighted when people here came through swimmingly on my earlier short-story query. Ta.)
