There are various theories about the secret to a happy relationship, but a new self-help book has caused a stir by suggesting we handle our relationships the same way we would a business. The authors of new book Spousonomics: Using economics to master love, marriage and dirty dishes, Paula Szuchman and Jenny Anderson, have applied the rules of capitalism to marriage and found the method can help couples manage their time, money and even their sex life.

Szuchman and Anderson have split their theory into seven relationship habits that they say are big relationship mistakes. The biggest mistakes Szuchman and Anderson say couples make include sharing the housework evenly, waiting until you're in the mood to have sex, and staying up all night to finish an argument.

According to Szuchman and Anderson, while you might think sharing household chores 50:50 is the fairest way, it actually means you'll always be keeping scoring and bickering about who has done more or less. The Spousonomics theory argues each person should do what they're best at, similar to what economists call "comparative advantage". This way the household will run more efficiently and there'll be less to fight about.

In regards to waiting until you're in the mood to, you know, do it, Szuchman and Anderson say months may go past without any bedroom action.

According to the Spousonomics method, couples should apply the hot-cold empathy gap developed by economist George Loewenstein to their sex lives. The theory suggests we each have two selves: a cold, clear-headed rational self that thinks, "I want to sleep with my partner tonight because I love them and I know it will be good for our relationship" and a hot, impulsive, emotion-driven self that says, when the time comes, "I'm too tired for sex, I can't be bothered — we'll do it soon."

Szuchman and Anderson claim we should listen to the "cold" or rational self and, to steal from a popular sports wear brand, just do it. We might not feel like making love now, but we did before. By listening to our rational voice rather than being controlled by of the moment emotions, a couple's sex life is likely to vastly improve according to the theory.