How to view this film (spoilers)

Spoilers:

There are some interesting theories here on the nature of the relationship between the man & woman in this film.

I think trying figure it out - like it's a puzzle - is the wrong approach. Just like trying to figure what a song or poem is "about" is a flawed approach to art.
(Plus each theory is a square peg in a round hole - - there are facts which contradict each theory.)

Two basic relationships are presented: 1. two middle-aged people meeting for the first time; and 2. a couple who have been married for over 15 years.

However, the relationships are not the only thing that is different. The people themselves are different. One couple is a "copy" of the other. Of course, the main theme of the film is that a copy can be as good as - or even better - than the original. So it doesn't matter who is real and who is a copy.

The first switch - from people meeting for the first time to a married couple - occurs about halfway through the film. In the last 10 minutes or so of the film - the hotel scene - they continue to switch back and forth. In the end we are not sure which ones we are watching.