There were some heated moments between the couple, especially following an alcohol-fuelled evening.
The plot in the TV adaptation has taken a very different turn to that in the book, as Kate and Johnny do not get divorced in the source material.
There is a lot of tension surrounding their separation as in the book they have their difficulties, but they stay together throughout.
Fans are wondering why the series decided to take a dark turn, and they have taken to Reddit to discuss the plot.
One user said: “I’m honestly still not understanding why they’re divorcing. Is it because he wants to follow his dreams after his daughter has grown up and that means he will be away for a period of time?
“Because he gets really involved and passionate about his work? Like what? Those are such flimsy reasons for divorce. They clearly still love each other and like just gave up.. either that or I’m totally missing something.”