He claims to have saved hundreds of thousands of marriages.
But John Gray, author of Men are from Mars, Women are from Venus, is worried by where relationships are going - notably online.
Free internet porn is "like taking heroin", while online cheating websites can also lead to sex addiction.
Gray, whose books including the original 1992 classic have been published in 50 languages and sold 50 million copies, is also worried about feminism, which he blames for rising divorce rates.
"The reason why there's so much divorce is that feminism promotes independence in women," he said. "I'm very happy for women to find greater independence, but when you go too far in that direction, then who's at home?"
Gray said widespread feminism in America held back sales of his books, while other parts of the world were more in tune with his basic message: Men and women come from different planets, and the two sexes should stop trying to behave similarly, and embrace their own natural personalities.
"The most resistance I get to my message is in America. Wherever feminism has a strong hold, there's resistance to the idea that men and women are different," he said. "When you go to Australia, for example, there's a very clear knowledge that men and women are different."
Gray, meanwhile, is ambivalent about the impact of technology on relationships.
Being able to meet people easily online had its pluses he said, citing the number of divorcees in their 40s and 50s who seek out former friends and partners.
But he voiced concern about two online trends: internet porn and the huge success of so-called cheating websites.
"With free internet porn, there's a massive addiction happening... just millions and millions of people are experiencing their sexual satisfactions through total fantasy," Gray said.
"The effect that porn has on the brain is like taking heroin."
Cheating websites were equally dangerous to real, long-term loving relationships.
"When you have impersonal sex.... 'It's OK, here are these cheating wives, men, they want to have sex with you'. So you go have sex with someone you don't know and someone you don't love... impersonal sex does promote addiction to sex," he said.