Betrayal (1983)

The story of an adulterous affair, told backward.  We see the denouement, the breakup, the middle, the early, and the very beginning.  It was effective because of the way my emotions were reversed: I didn't know/care about these people who were reflecting on the "once was" and was only mildly interested in the next scene...but my involvement grew which each new, earlier revelation.  It was strangely powerful and fascinating.

A-

Here's the beginning of the affair/almost last scene of the film: