Guys talking\\"Five Mortifying Things He Tells His Buddies"\\Photo: Anna Palma, courtesy of Cosmopolitan

John Mayer raised more than a few eyebrows when he publicly declared that being with Jessica Simpson was like "sexual napalm." We were surprised, but frankly, this isn't the first time we've heard a man run his mouth about something so private. And current flames are just as likely to talk trash as ex-boyfriends.

"Most men don't understand proper relationship etiquette and don't think before talking about things you thought were just between the two of you," says New York City-based couples therapist Rachel Sussman. "It doesn't occur to them that it might be personal." We got the dirt on why he thinks it's fine to share everything from your beauty habits to your secret kinky side so you can at least understand the cause of his verbal diarrhea ... even if you may not be able to stop it.

1. You Wax Your Upper Lip
We all want guys to think we wake up looking amazing — whether we're sleeping with them or not. So it's mortifying to know that his buddies are aware that your look takes work. But, believe it or not, he's actually giving you a compliment when he yaps about your embarrassing beauty regime. "He's basically saying, 'Look what this girl does for me. She's going through all of these painful things to look beautiful for me,'" says relationship expert Terri Orbuch, Ph.D., author of 5 Simple Steps to Take Your Marriage From Good to Great. He's also used to hearing you talk about this kind of stuff with your girlfriends, so he assumes it's cool for him to do the same.

2. You Just Had a Raging Fight
It's irritating to know he's rehashing your latest brawl with his buddies, but let's be honest: We do it, too ... and probably go into even more drawn-out detail with our friends. "Everyone deserves support from their friends and it's perfectly normal for him to want to talk it out with someone else," says Sussman. He's also trying to find out whether this kind of fighting is normal in a relationship, says Orbuch, and to get confirmation that you were a total psycho bitch when you asked him to stop playing Super Mario Galaxy while your parents were visiting.

3. He Got Some Action Last Night
Whether you've been together for three days or three years, your guy has probably bragged to his friends about bedding you (and he'll do it again). But most men would be surprised to know that offends you, since they're just trying to one-up their buddies. "Guys have been doing this kind of thing since they were five years old," says Sussman. "It's how they relate to each other." To him, touting his own accomplishments to his crew is as natural as you telling your BFF the results of your recent shopping excursion.

4. That Time You Accidentally Flashed His Grandma
Remember that hilarious and extremely embarrassing memory you've never told anyone about but him? Yeah, well, a half dozen of his guy friends probably heard it the next day. Don't worry, odds are they'll never repeat it or even think about it again. "Men feel most comfortable talking about things that are light-hearted and funny, and they'd rather share a laugh with their friends — even at your expense — than talk about how much they love you or anything else remotely serious," says L.A.-based relationship therapist Seth Meyers, Ph.D.. So the story about how you once laughed so hard you accidentally let one rip is just one of countless funny anecdotes that'll be forgotten by the time someone buys the next round.

5. How Much Money You Make
If you're private about money, it's seriously annoying when your guy's best friends casually refers to your salary, right down to the second decimal point. And we know who slipped him that info. Chances are, it's because your guy is psyched about the fact that you make so much. "Men usually only talk about how much their partners make when they make more, because they think it makes them look more powerful and in-control to their friends," says Meyers. And men love to brag about money, period, meaning everything from that amazing rent you negotiated to how much you saved on your car payment is fair game in his mind.

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