Ten years down the line in a marriage, most couples find it hard to keep their relationships steady, but that's not the case with soccer ace David Beckham and his wife Victoria.

"Separate interests keep their love fresh and alive. They make the most of, and live for, the time they spend together," says Quilliam.

David's downfall came in 2004 in the form of Rebecca Loos, 32.

"The Beckhams were obviously able to talk through their problems, learnt to understand one another, and then put it behind them," says Quilliam.

The Beckhams have produced a hat-trick of gorgeous sons: Brooklyn, 10, Romeo, six, and break-dancing Cruz, four.

"When you're in a loving marriage and know you can weather any storm, having a child can bring you even closer, provide a focus for your love and give you a shared job to do," says Quilliam.

"Victoria's made many sacrifices, but both have genuinely admired and supported the other. Be proud of what your partner does -- and tell them so," says Quilliam.

"It's a sign of disrespect to your partner to let yourself go. By taking care of themselves, David and Victoria help keep the lust alive," says Quilliam.

"While individuality is important, their 'matching' styles, and the overlap between them, shows the world they have a rock-solid partnership -- they think, feel and act the same," says Quilliam.

Victoria and David travel thousands of miles to spend one night together.

"They're constantly declaring their love. Just saying: 'I love you' every day goes a long way in keeping romance alive," says Quilliam.

The secret of a happy relationship is a happy family. With their hectic schedules, David and Victoria would be lost without Sandra and Jackie, their respective mothers-in-law, who regularly travel with the family, acting as babysitters and allowing the couple to spend precious time alone.

"The Beckhams know the importance of making their mums feel involved and valued. They give the family stability and are a vital source of support," says Quilliam.

Behind the scenes, Posh and Becks have had their fair share of humdinger rows. But unlike other celebrity couples, they're careful never to argue or criticise each other in public.

"David and Victoria have such a public profile that even the slightest hint of tension would quickly come back to haunt them. They never criticise or bad-mouth each other, and if anything negative happens, they close ranks," says Quilliam.

Posh is regularly seen scouring LA's sex shops and stocking up on red-hot goodies. And David often buys sexy underwear for his missus.

"Love thrives on physical passion. Shared pleasure and sex binds them together and helps them get through stressful times," says Quilliam.