Are you worried that your partner might cheat? Well, according to one relationship expert the clue is in their payslip.

Before you start searching for signs or looking for evidence of infidelity, India King says the best way to find out if your partner has the potential to stray is to refer to their income.

Speaking to Femail, she revealed that men or women who earn more money than their partner may be unfaithful; especially if they feel they’re not given the respect they deserve.

She adds that as long as the lesser earner shows 'gratitude and appreciation' for the higher earner all should be well.

But, problems may well ensue if they become entitled or stop being grateful.

While King says that this theory works both ways, she adds that it’s particularly important for women to treat high-flying men with respect. It all sounds rather old-fashioned and sexist to us.

She argues: “Respect for men is like oxygen, men crave respect. If you respect him, he will cherish you.”

The gender stereotyping doesn’t stop there; oh no.

“Men know it's their role to protect, provide and support. It's the woman's role to receive gracefully, and also to show gratitude and appreciation for his efforts.”

She goes on to explain that if the woman doesn’t conform to her ‘role’, then the man is like to “take his efforts elsewhere, to someone who will make him feel valued.”

King also asserts that in the same way, if a woman also constantly nags or criticises a man, he will naturally show her door.

The 1950s called, they want their relationship advice back.