For some reason, you suspect your beau might be cheating. Maybe you're worried because it seems to be happening all around you. Maybe you really have reason to be suspicious. (After all, if Jude Law can cheat on Sienna Miller or Hugh Grant on Liz Hurley, what hope do any of us girls have?) Either way, it's time to find out once and for all.

Here's how:

1. Visit him at work
Start dropping in on him at work. Use this opportunity to see if your photo is still on his desk, go through his office garbage, maybe sneak a peek at his desk calendar. Are there a lot of lunch dates? Special events after work? Any birthdays you aren't familiar with? Go through his desk drawers. Cologne, toothbrush, condoms--all bad.

2. Hug him--a lot
When he comes home from work (later than he said he would) greet him at the door and give him a great big hug. Smell him for signs of perfume, alcohol, smoke, or sex. These are all out-of-the-ordinary smells for someone who was supposed to be working.

3. Go through his dirty laundry
You can learn a lot from dirty laundry. It's almost certain he's cheating if you notice he has new underwear. If you find he's thrown out the underwear that's ripped or have holes in them, it means he's decided he can't be seen in them anymore, even by you. (Men never suddenly decide to throw out underwear, even the saggy ones that show their hairy butt crack.) Next, give the new underwear a sniff. If they have the fruity smell of personal lubricants, bingo!

4. Call back
If you get a lot of hang-ups, jot down the numbers and call them back from a payphone. When the person answers, don't say anything and see if you can recognize their voice. Hang up so you don't give away that you're closing in on them. Just steel yourself in case the voice you hear is the voice of your best girlfriend.

5. Snoop
Be a snoop. Go through bags, coat pockets, garbage cans, anyplace you might be able to find a clue that he's sneaking around behind your back. You're looking for movie stubs, condom wrappers, or restaurant receipts. Find out where he's eating. If it's far from work and home, he might be eating there because he doesn't want to get caught. Now that you know where he likes to eat, you could start randomly dropping in.

6. Analyze your sex life
If you're still having sex with the low-life bottom feeder, be suspicious if he's suddenly very adventurous and wants to try new tricks or appliances in bed. Has he suddenly mastered an old maneouvre that he used to fumble through? Where's he getting all this extra practice? You should probably start denying him access privileges.

7. Analyze his spending
When men cheat, they have to start spending money. So become an expert on your finances. If they're not shared, you're going to have to start snooping through pockets for receipts. If he says he's doing a lot more work on the car, and your finances are shared, ask for receipts.

8. Late-night chatting
Does he stay on the computer long after you've gone to bed? He's probably chatting with her online. And of course you want to know what he's saying almost as much as you want to know what she's saying. You can download software onto your home computer that allows you to monitor remotely what's being written. It will even provide reports of websites that he visits and will include online passwords--useful when you're looking for proof that your partner is a cheater. You should also buy a nanny-cam. You can even buy one that also works like a clock radio. This is particularly useful if you're often away from home for business and you want to see what's happening in your bed. Make sure that when you watch the tape, you have a posse of girlfriends within dialing distance.

9. Play detective
You can always follow your partner to see where he goes. This is best done with a friend's car, but can even be done in a taxi. Wear sunglasses and a hat to make sure he doesn't see you. If you know where he's going, you can send a surrogate spy on your behalf, someone he won't recognize. Try sending someone who's willing to spill a drink or drop a bowl of soup on his lap if he does happen to be meeting her. Anything that can wreck his night out.

10. Stake him out
As extreme as staging a stake-out is, the ultimate way to check for infidelity is to pay someone to test for DNA. Find a strange stain on your bedsheets? Snip it out and send it to a lab for infidelity testing. You can eliminate yourself as the source by including a mouth swab. The tests cost anywhere from $300 to $900 but it's money well spent to tell you what you need to know before you kick his ass to the curb.

Once you've got the goods to prove you were right all along, what are you going to do? Make him pay. Make his last days with you unbearable. You don't need to stay friends or work through it. Then, get your hair done, buy some new shoes, and plan a night out with your girls. And if he's got a good-looking best friend, get him into bed. Nothing will piss your ex off more. Happy hunting!

Written by Reni Walker

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