I write about the part of love nobody photographs: the week you spend wondering, the conversation you rehearse in the shower, the moment you decide to stay or to go.

Everything I write starts from the same refusal. I will not give you a list of signs that prove someone is unfaithful, because that list does not exist and selling it would be dishonest. What I can give you is the psychology behind the behaviour, three explanations for every change instead of one, and the words to use when you finally sit down to talk.

The couples in my books are invented. Some of them are cheating, some are not, and in some the real problem turns out to be something else entirely, because that is how it goes in the world. The feelings are the part I did not invent.

Every book comes out in five languages at the same time, written out in full in each one, with its own examples and its own scripts, rather than run through a translator.

I am not a therapist and these books are not therapy. If what you are living through is affecting your sleep, your work or your ability to get through the day, please talk to a professional near you. A book can explain. It cannot sit with you.