Men/Women divide
The ancestral divide between men and women shows up every time a couple has nothing of valour in common, doesn' t share a passion, or every time there's a power imbalance between the man and the woman making up a couple.
At the beginning of the film I thought Therese was a strong woman, capable of standing her ground and fight for (and get) whatever she needs and believes she deserves. By putting the extra drops in her husband's water, she broke the rules. I cannot believe she did not choose to break the rules by taking charge of her own life and happiness.
Seeing her reduced to an almost vegetative state later on was painful to watch.
I absolutely loved this film, and Tatou did an amazing job playing Therese!