My dream deciphered their true relationship - SPOILERS!
I went to see this film on Saturday and that night I dreamed about the film, I was dreaming that I was figuring the film out, and it became very clear to me the following:
Juliette Binoche's character was the man's mistress, had a child by him, but he just wouldn't marry her how she obviously once thought he would, hence their relationship can be seen as a 'certified copy', ie, not the real thing. Hence her obsession with weddings, hence her strange reaction when their son asked 'why didn't you want him to sign my full name in the book?'...ie, because the son does not have his surname. Hence her saying she's a 'single mother', hence her telling him that the waitress 'thought we were a married couple and I didn't tell her otherwise'... etc.
The anniversary they were celebrating was their 15 years together, not their marriage. This also explains why he stepped outside to take calls on his mobile, to talk to his wife. When he took a call outside when they were in the cafe, and the older waitress said to Juliette, 'he has a mistress... that's why you are looking at him'...and she said 'no', she put on a strange face....because actually she herself was his mistress.
At the end when she asks him to stay at the hotel ....to not catch the 9pm train (to his wife), it is probably something she has asked him hundreds of times before, hence his exasperated look....the man caught between two women. Hence, he was defending before 'the copy', in other words, implying that their relationship was like a marriage, that it didn't matter that he was legally married to another woman. Of course, just like in a true marriage, after 15 years together their relationship has become more of a 'warpath', time increasing their obvious differences.
Does the film and their relationship make sense in that context?