Her future husband had a lot of female friends - some of them ex-girlfriends. ''I suppose that I felt insecure, particularly as these women knew him better than I did and made a point of letting me know,'' she says.

Though he never behaved secretively, she tried to listen in on phone conversations, glimpse his emails and keep tabs on him at parties. ''There's no doubt it was a stressful time,'' she says. ''Maybe if I'd been more laid-back we wouldn't have had so many incendiary rows. But hey, we survived it.''

Snooping, or, as psychiatrists call it, ''covert intrusive behaviour'', is as old as time, but the proliferation of technology can fuel mistrust. In a survey of 1250 people, Telstra found 40 per cent of women checked their partner's mobile inbox and 24 per cent claimed to have caught a partner flirting via SMS.

But women are not the only ones who snoop. Private investigator Warren Mallard says 40 per cent of his clients are men, a marked change from 30 years ago.

''It used to be that 80 per cent of our clients were women,'' he says. ''Women aren't stay-at-home carers so much now. They have comparable incomes and more opportunities to meet people at work, so they are having affairs just as much as men.''

A relationship counsellor with a private practice in southern Sydney, Elly Taylor, says snooping generally occurs for one of two reasons: someone is insecure (even though their partner is perfectly trustworthy), or they have real grounds for suspicion.

Those left feeling insecure after bad experiences with previous partners may snoop to protect themselves but, Taylor says, it is never an answer to the underlying problem of low self-esteem and trust. ''I don't think snooping can ever be healthy behaviour,'' she says. ''It's a violation of privacy and shows a lack of respect that creates mistrust and distance between couples.''

When Elana Kubrich* found romantic text messages to her fiance on her housemate's phone, she hacked into her fiance's emails and confirmed the affair. She ditched her partner - and her housemate. She admits the experience has left her more ''curious'', with an urge to snoop.

''I had one partner who I met online,'' she says. ''When I was using his laptop, I checked his internet history and saw that he was still using online dating sites. I had another ex who was very secretive about his phone, so I checked it when he was in the shower and found he was buying drugs.''

Kubrich says she saves her snooping for genuinely suspicious circumstances. Her present partner shares his phone with her and they are open with each other. ''This complete honesty … means I have never had any questions about whether I can trust him and I've never felt the urge to snoop.''

* Names have been changed.

Resist the urge

❏ Maintain a sense of self, as well as a sense of the relationship. It is neither necessary nor healthy to know everything about another person.

❏ If your partner seems to be cutting you off from part of their life, ask why. Keep things open and transparent.

❏ Think about whether your suspicions are grounded in reality. If you feel anxious, it might be worth seeking advice from a counsellor.

❏ Tell your partner how you feel without laying blame. If they feel attacked, it can lead to more secrecy.

Source: Relationships Australia