title wanted

[sandmaster]

In the 60s I read a book where Chapter 1 started with a married couple in bed. She's asleep, he's going to prison the next day. Their marriage is tired. He tries to manoevre her into a position where he can have sex but she wakes up and tells him not to be silly. It was an hilarious book - not sexual as this first chapter would imply. Does anyone know the title and author and where I can get a copy?