Can people make someone kill themselves without any visible trace?
If people who have heard of gaslighting, they might think about the couple as an example of gaslighting.
And the film, gaslighting, is also about the happening between the couple.
It is very hard to know there is the problem in the relationship when people look at them outside. Often, the couple looks enjoying a very happy, normal married life more than other couples.
But when you listen to the conversation, you will see that the man keep lying and cheating on her but make it all her fault.