What was this movie based on?

It's a pastiche of the 1955 film "All That Heaven Allows", directed by Douglas Sirk and starring Jane Wyman and Rock Hudson.

In "All That Heaven Allows", Wyman plays a middle-class widowed housewife who falls in love with her gardener, played by Hudson. In conservative 50s small town America, this relationship could never work and they can't be together despite being in love.

In "Far From Heaven", Haynes changes the one forbidden relationship into two; ie a gay one and an inter-racial one. Obviously, neither of these could have been tackled in the 50s, but the sentiment of forbidden love remains the same.

I really recommend that you watch "All That Heaven Allows" as it's a wonderful film. Douglas Sirk was the king of the melodrama and it stands up well as a piece of cinema. It's also interesting, with the benefit of hindsight, to look at Hudson's performance and think of the fact he was hiding his own sexuality in real life.

Also, there are some scenes which are virtually shot-by-shot redos in the Haynes film and it's good to compare and contrast them.