When John Gray's international bestseller Men Are From Mars, Women Are From Venus, first hit the shelves back in 1992, he became an over-night success. The book shed light on countless relationship problems, offered an explanation for many social inequalities and became a hot topic of debate.

But that world has moved on. In Gray's latest book Why Mars and Venus Collide, the American psychologist looks at how the pressures of our 21st century work-driven lifestyles are putting even more stress on our relationships, making it harder for them to work out long term.

He said: "The unprecedented level of stress both men and women are now experiencing is taking a toll on our romantic relationships, so we are often too busy or too tired to sustain feelings of attraction, motivation, and affection."

This is exacerbated by the contrasting - and mostly incompatible - ways in which men and women deal with such stress, according to Gray.

The biggest problem at home, he said, is women expect men to react and behave the way women do, while men continue to misunderstand what women really need.

He said: "What helps men release stress can be the opposite of what helps women feel better.

"While he withdraws into his cave to forget the problems of his day, she wants to interact and discuss things. When she shares her frustrations, he offers solutions, but she is simply looking for some empathy.

"Men tend to shift gears, disengage and forget their problems, while women are compelled to connect, ask questions and share problems. So when a man needs time alone and doesn't want to discuss his day, it doesn't mean that he cares less for his partner, and when a woman wants to talk about her day, it doesn't mean that she is excessively needy or high maintenance."

But as we approach Valentine's Day, is it all doom and gloom for our relationships?

Not so, according to Gray. The solution is to be aware of our innate biochemical differences and celebrate them.

In order to make your relationship a sanctuary from the stress you encounter everywhere else in your life, Gray advises that you also have to drop the expectation or hope that your partner will be perfect.

He said: "Letting go of the notion that your partner should be the primary source of love in your life is one of the smartest decisions you will ever make.

"By taking responsibility to nurture and be nurtured by other sources of love and support, you relieve your partner of this impossible burden."

Finally, Gray argues that it is unhealthy to want your partner to be just like you.

"Shared likes and preferences create comfort, but too much comfort creates boredom.

"The differences between a man and a woman create attraction and passion, and you also need to create some distance, because to experience the excitement of coming together, you must also spend time apart."