Elvis Presley was right: one of the things guaranteed to drive a couple apart is a suspicious mind. Once implanted, those little seeds of doubt can niggle and grow, causing distress, unhappiness and eroding trust. Janine remembers clearly the first time she had her suspicions about ex-husband Lou. 'I'd been away for five days on a course and managed to get on an earlier flight home. I walked through the door about three hours ahead of schedule to hear the phone ring and switch to the answering machine. 'It was one of Lou's colleagues apologising for bothering him on his day off and asking could he call him back as something urgent had cropped up. But as far as I knew, Lou wasn't on a day off. He should have been at work and when I tried to call his mobile it switched straight to voicemail.' Lou arrived home at his usual time and gave Janine a huge hug and said he missed her. When she mentioned the call, he said he had been called to a last-minute meeting with a client in Kowloon and that his colleague had got it wrong. 'I tried to act like I believed him,' she says. 'I thought I was being silly not to, but there was something about it that made my stomach turn. I suppose it was because deep down I could tell he was lying.' Janine tried to put her suspicions to the back of her mind, but found herself trying to catch him out. 'I didn't follow him or anything like that,' she says. 'I'd do things like call his office more often and pay more attention when calls and messages came on his mobile. 'One day I'd be convinced he was seeing someone else; the next I'd be convinced he wasn't and would feel so guilty about not trusting him. I'd think, 'You stupid woman, how would he feel if he knew you'd been checking on him.' The crunch came when in desperation Janine decided to talk to a close friend. 'I expected her to say, 'Don't be so silly'. She didn't. She said, 'Maybe you're right'.' It turned out that her friend's husband had seen Lou at the airport with another woman, acting more like a couple than business colleagues.' It was all the evidence she needed. When confronted, Lou admitted the affair. Some studies show that suspicions about partners having an affair turn out to be right 90 per cent of the time, says Raj Persaud, a consultant psychiatrist at London's Maudsley Hospital. In his book Simply Irresistible: The Psychology of Seduction, Persaud devotes a whole chapter to extramarital affairs. He points out that the business trip - some-thing many Hong Kong men take often - is one of the strongest predictors of marital infidelity. One survey found that when businessmen travel, they're twice as likely as a holiday traveller to have sex with someone new. But before you rush out and hire a detective or challenge your partner head-on, you should first be sure whether your suspicions are reasonable or just the product of a jealous mind, says Johnny Chan Kwok-ping, a clinical psychologist and relationship counsellor. 'Use your common sense,' Chan says. 'Ask yourself if your suspicions make sense or are valid. Some people are too sensitive and react if their partner just looks at the opposite sex. How can you tell if you're too sensitive? Talk to your friends. Tell them about the situation and ask them if you're being too sensitive. 'If they say yes, then try to control your suspicions. But if your friends say you're being reasonable, then you have to do something.' What you shouldn't do is let your suspicions fester, so they take control of your life. 'Some people may not care,' he says. 'They choose to ignore their suspicions, which may subside or calm down. But if they continue to disturb you, if you can't forget them, if they keep running over in your mind all the time, then you have to talk to your partner. Talk is very important.' Raising such a subject isn't easy. But if you choose not to face the issue and choose not to talk, you risk breaking the communication channels between you and your partner, which in turn could cause irreparable damage to your relationship. If your partner refuses to talk, it could be a sign that your relationship has already died, says Chan. Richard Gee, of the ReSource counselling centre, says there's only one thing to do in this situation: talk. 'If someone has a suspicion and they're keeping it to themselves, it's going to affect the way they relate to their partner,' he says. The danger of harbouring suspicions or going to the extreme of hiring a detective is that, if you turn out to be wrong, you face the dilemma of whether to tell your partner you've been checking up on them, says Gee. 'Do you admit that for the past two months you've been freaking out because you thought they were having an affair, and that's why you've been behaving so horribly towards them?' he says. 'The best thing is to put it down on the table right at the start and say, 'Hey, this is what I feel. It's weird that you come home with lipstick on your collar. What's going on?'' Helene wishes she hadn't chosen to ignore her fleeting suspicions about her husband Jon, who turned out to have been having an affair for eight years with a woman he met on a business trip in Bangkok. 'The signs seem obvious looking back: business calls on the mobile at all hours, regular business trips overseas that spread over weekends, a sudden interest in hair products, a reluctance to engage in conversation or even eye contact, a withdrawal from family activities, more time spent on the golf course and excuses found not to spend time together as a couple. 'I did challenge him on a few occasions and he told me what I wanted to hear, so I didn't take it further. I suppose I was occupied with bringing up a young family and working. I refused to see the obvious and he didn't seem the type. I made excuses for his coldness and selfishness and tried to convince myself that he did really care for me.' But Helene had to face the truth when she came across a pile of letters and documents in her husband's study. The documents included letters from the woman, bank transfers to an account under her name and even documents from immigration filled in by her husband trying to get the woman a visa to enter Hong Kong. It was the end of the couple's 18-year-marriage. With hindsight, Helene says she wishes that she'd done something sooner. 'Looking back, I feel as if I wasted so many years trying to salvage a marriage that was doomed. I just wish I'd trusted my feelings.'