My alternative ending

I came up with a different ending. In fact, it’s not that different from the current ending:

As Amy kneels beside her husband she realizes he's dead. Then we see a short flashback of when they were hiding in the gas station: when David says to Amy that she shouldn't blame herself. He was talking about the accident of their son (= the reason their marriage failed).

By showing this again, at the end of the film, the words get yet another meaning… her thinking about those words imply that she now also blames herself for the dead of her husband. Even though she is not to blame, she feels like she could have done more to save him and their marriage.

The camera pans out as she grief’s over his body.

What do you think?