"We have to look at ourselves and what we can do differently and how we can creatively manage (the relationship) ... because it's otherwise not magically going to change if people do the same thing."
While, the book was geared towards women, both partners needed to be involved in the relationship to make it work, she said.
"It's not uncommon for women to revert to a cultural norm of criticising, feeling disappointed in their partners and highlighting and communicating what's wrong, rather than celebrating what's right," French said.
Men tended to shut-down communication, have contempt and criticism when the relationship was going downhill.
The trick was to remain calm when bringing up a problem in the relationship.
"It's not just about being a doormat and letting them speak to you in whatever way they want to and then thinking 'Oh my God, it's my fault"', French said.
The partner needs to react in a calm, compassionate, natural, "naive inquirer" fashion to encourage communication, she said.
"It's less about going 'I need', or 'I want', and it's really being curious as to where the other person is coming from and why they're doing what they're doing and how they feel about what they're doing.
"Then you can make compromises and making deals with each other about stuff."
Many couples came to therapy blaming each other for the relationship deteriorating - "so it's a matter of stopping that to find out the reasons behind [the problems]".
"The only relationships that can't be saved is if someone is a sociopath, if there's abuse present, power and control, active addition, then you're screwed."
