The Nature of Love is about a gal who ditches her hubby for a paramour.
The shot that marks the final moment of their marriage is strikingly framed, lodging it in our memory for when the framing is repeated in the closing-credits: each actor’s name is accompanied by a picture of their character, framed in the exact same manner as the aforementioned shot.
Which seems resonant in a movie about the cyclicality of never being completely satisfied with one partner. Our last glimpse of every major character is defined by framing that earlier conveyed the permanent fracturing of mutual love; does this suggest that their relationships are doomed to be inevitably framed by a similar dissolution? At the very least, they — and all humans? — exist in relation to this potential endpoint.
Even the marketing campaign understands the importance of this framing, as evidenced by the French poster utilizing the very same imagery:

Also, this bloke isn’t even her hubby! He’s the paramour!
And given what this framing signifies in the movie proper, the poster can be interpreted as a retroactive spoiler.