How to spot a cheater

Dan and Julie met in college and moved in together after graduation. A couple of years later, Julie picked up a phone bill and noticed a disproportionate number of calls to her ex-flatmate. "Then I realized I hadn't called her in months," recalls Julie.

She questioned Dan about the calls, and at first, he denied he ever made them. "Then his story changed — he said he just enjoyed talking to her," Julie says. "But the more he said, the more I realized he was lying."

After his initial denial, Dan blurted out that he had been cheating on Julie with her old flatmate since university. He realized there was no getting around the hours and hours of phone calls she had found. "I had caught him simply because of a phone bill," Julie says. "Without it, I don't know if I would have ever found out."

Although Julie had no reason to suspect Dan was having an affair, her antennae went up because of a specific clue. "I found something I didn't even know I was looking for," she says.

It's not always easy to spot a cheater. But there are a few quick ways of determining whether a bloke will stay true to you:

1. The Houdini act

If your man suddenly becomes incommunicado, and then offers lame excuses about his absence ("my mobile went dead", "the boss wouldn't let me out of his office"), chances are he's with someone he's not supposed to be with.

"I fell for the excuse that Charlie was always away from his phone when I tried to call him," says Claire about her ex-partner. "Then I realized that as a salesperson for a software company, he should have been able to be reachable 24 hours a day. He carried a mobile with text service. It turns out he was having an affair with his co-worker."

2. The slip-up

Emily adored Tim. Until one night, in the heat of the moment, he called her his "little tiger woman." "He never called me that," she says.

A couple of nights later, he suggested that they go back to the new sushi restaurant that recently opened on the other side of town. "We had never been there together," Emily recalls. "And I guess he forgot that I was highly allergic to shellfish. That's when he told me he was seeing someone else."

3. The cold shoulder

If your once-sizzling love life has fizzled, chances are your man may be finding love in other places.

"When Liam began rolling away from me each night in bed, I knew something was wrong," says Jill. "At first, I thought our relationship had hit a lull, but then I found that his electricity was directed somewhere else."

4. The compulsive cleaner

If your guy suddenly becomes a little too concerned about how quickly his clothes are laundered, how often the car is washed and how frequently email is deleted from his computer, chances are he's hiding something.

"Adam was never the type of guy who was overly concerned with putting things away," says Emma. "Then, he would come home late from work, jump in the shower and wash all his clothes."

While clearing out the dryer, Emma found the remnants of a love note in Adam's trousers from the night before. "When I read the note, I understood why he felt so dirty when he came home."