This story appears to fit in with the version of time travel presented in
The Far Side of the Bell-Shaped Curve, only a different type of dilemma is explored: what if a time traveler, instead of visiting the great moments of history, became obsessed with getting back an ex-lover? The scenario presents a very fluid vision of reality— with the past changing constantly, everyone accepts new situations with a casual attitude. After a moment of disorientation, you go on with a new version of your life. It's technically illegal to manipulate the past for private game, but how can you prove a crime when the very success of the crime eliminates it from the past?
Mr Silverberg informs me that Miramax studio has purchased the rights to make a movie of this story, though at the moment there is no timetable for production or word about who might write, produce, direct, or star in such a film (if it's ever made).