As musical star Darren Day tries to win back pregnant fiancee Suzanne Shaw after reports he cheated on her with a chorus girl, Women's Editor Lindsay Jennings asks why do women put up with love rats?

SNUGGLED up under the duvet at their Hertfordshire home, Suzanne Shaw and Darren Day were blissfully unaware of the bombshell which was about to drop through the letterbox.

As the celebrity couple lay cuddled up in bed, a letter was being posted through their door by a tabloid journalist containing allegations that Day had been unfaithful.

Even though the name on the slip of paper was wrong - Day had actually spent the night with a chorus girl called Cecilia Carneby - the hurt and the pain tore through Suzanne, who eight months into her pregnancy was at her most vulnerable.

The note fell almost a year to the day that the five-times engaged West End musical star pledged his love-rat days were over. He'd developed the tag after a string of failed romances - ditching actress Anna Friel before professing his undying love for Coronation Street star Tracy Shaw and later moving on to Home and Away actress Isla Fisher and dancer Adele Vellacott.

Hear'Say singer Suzanne, 22, and Day, 35, got together after starring opposite each other in Joseph and The Amazing Technicolour Dreamcoat. Pledging his new love for her, he said she was "like my kindred spirit".

But those words must have been ringing in the ears of Suzanne, along with promises of being "120 per cent faithful", as she fled to her dad's home in Bury, Lancashire last week. The pregnant star will have been even more confused over what to do after Day complicated matters by insisting that he was innocent. It's one thing a love-rat admitting he's done wrong and begging for forgiveness, but another if you have the added dilemma of having to believe them if, as in Day's case, they claim nothing happened.

Says Dr Linda Papadopoulos, reader in psychology at London Metropolitan University: "The fact that the men are able to attract a women when they're known for cheating is probably down to them being very skilled in knowing how to impress and compliment a woman.

"I think once they're together, women do convince themselves that this time it will be different. But there are also lots of reasons why they stay with serial cheaters. Some women may have low self esteem. Women generally are very trusting and they believe what the guy says. Also if they had a background where the father did this kind of thing there's an inevitability that boys will be boys. Others are simply frightened of being on their own.

"It also depends on the person who has cheated and how willing they are to be honest and how they make amends."

Suzanne Shaw says that her pregnant condition has left her with no option but to believe her fiancee - despite his appalling history with women. After initially being furious with him, she has also conceded that she does not want to be alone and a single mum.

"I just have to believe him for the sake of my unborn baby," she told a national newspaper. "I know that people are going to call me a mug, but at the end of the day, I know Darren and what our relationship is about and only I can make that judgement."

Christine Northam, a senior counsellor with the relationship support service Relate says that anyone who has been cheated on will go through feelings similar to a grieving process as they struggle to grasp the situation.

"It would be a huge shock to find a partner had cheated on you because when you're in a committed relationship the reason it's committed is because you believe in it," she says. "You go through a kind of grieving process because you have lost what you thought you had. You need support from friends and family to help you initially and also you need to find out what's happened and why it's gone on.

"Counselling can be beneficial in finding out why it has happened and help you both to work out what's behind the behaviour as we all have conscious and unconscious needs. But if you can come out the other side usually the relationship is stronger."

But the road to the other side is a rocky one, and before there can be any chance of forgiveness, many women feel they need to hear every little detail. Suzanne has reportedly told Day to dish the dirt on all the girls he's ever slept with before she can begin to forgive him. "First of all the person who's been cheated on usually has lots of questions and they keep on asking them because they want to know every little detail," says Christine. "They need lots of reassurance and to hear the truth about what's happened. But the perpetrator will often feel guilty and so might not want to talk about it.

"The person who's been cheated on needs to recognise that it's happened and allow themselves to talk about it and not to let it spill out into everything from then on."

A woman who knows only too well what Suzanne is going through is Victoria Beckham, who publicly declared her trust in husband David after allegations that he had an affair with former personal assistant, Rebecca Loos. Mrs Beckham's way of dealing with devastating stories about her other half has been to appear in public in an array of expensive designer outfits and a dazzling smile.

But if Day's love-rat stories continue, he may leave Suzanne with little choice but to walk away.

Says Christine Northam: "Most people don't go on having serial affairs - unless there's something psychologically amiss. But it usually ends when the person who's being cheated on says enough is enough."

* Mirror Mirror, The Body Image Revolution by Dr Linda Papadopoulos is out now (Hodder and Stoughton)