I saw a movie about 15 plus years ago. It was a French language movie about a man who wakes up with a different wife or girlfriend after he sleeps with her.
The wife/girlfriend doesn't realize that there is anything wrong and treats the man as if everything is normal and they have been together for a long time. The man obviously realize that his wife/girlfriend has changed and is confused, but then he likes the idea of getting a different woman to sleep with every night.
Then one morning he really like the new woman and so doesn't sleep with her. Over a number of days falls in love with her and so has the difficulty of wanting to sleep with her, but knowing if he does, she will disappear and be replaced by a new woman.
I can't remember the start of the movie and why the wife/girlfriend started to get swapped out or the end of the movie, but any clues as to what its called would be great.