We're so used to stereotyping men for having a bigger sexual appetite than women, for being selfish in the bedroom, and women have carved hundreds of thousands of articles trying to help other women keep up with their men in the bedroom.

But we may have to distort our views a little, because Abraham Morgentaler, M.D., author of Why Men Fake It: The Totally Unexpected Truth About Men and Sex, says, "We always talk about the differences between men and women, but I think we've exaggerated that." Morgentaler has been helping men with their sex lives for more than 25 years, and he's heard some very interesting things along the way.

You won't believe what some of them are:

Men Can—And Do—Fake Orgasms
In the case study that inspired the book, a man went to Morgentaler complaining that he didn't know how to stop faking orgasms with his girlfriend. He hadn't been able to climax during intercourse for most of his life, but since he really cared about his new girlfriend, he'd resorted to faking it so that she wouldn't get offended. And he's not the only one. "As this book was being written and I was talking to people about it, it was astonishing to me how many men said they've faked it in their lives," says Morgentaler. So what about the evidence? Of course, if you're using a condom, you probably wouldn't know if he disposed of it immediately. But "if you're not using a condom, it's often a question of how much fluid is down there and how aware is the woman," says Morgentaler.

A Male Orgasm Doesn't Always Come with Evidence
Apparently, in some cases, men can actually orgasm without ejaculating! For some men with diabetes, the opening to the bladder doesn't close well, and the fluid can go back into the bladder and only get released when they urinate after sex. Another slightly more common example is older men who have had a radical prostatectomy. And although Morgentaler isn't absolutely sure about this one, people who practice tantric sex often believe that men can experience an orgasm without ejaculating.

Men Fake it for the Same Reasons Women Fake It
According to most of the men Morgentaler has treated, the main reason for faking it was because it just wasn't going to happen for them during sex (which is also one of the reasons women fake orgasms). He could have simply had too much drink, or he's feeling anxious, or he's on medications for anxiety or depression that make it harder to orgasm. "It's almost the same as what happens with women," says Morgentaler. "It's a way of saying to their partner that they still did a good job, everything's fine, and it's enough for now."

Younger Men Have Problems With Erections, Too
It's not just the over 40 crowd that's seeking sex therapy. "Men—including young men—have a lot of sexual issues," says Morgentaler. "This is not rare by any means." And it's not just erectile problems that they're suffering—premature ejaculation affects about 20 percent of men, says Morgentaler.

Men Aren't Always in the Mood
Contrary to popular belief, "this idea that man are ever-ready, ever-willing is actually not true," says Morgentaler. "It may be true at 18, but things change once you have responsibilities." Women think it's normal for women to not be in the mood due to stress and whatnot, but assume men aren't affected by issues. But the truth is, they suffer from stress and all sorts just as women do, so it's totally normal for men to pass on sex every now and then.

Men Are Often More Focused On Your Pleasure Than Their Own
The myth about guys being selfish in the bedroom isn't true for all men. From some of the cases Morgentaler has seen in his practice, it's quite the opposite. Men, like women, are often more concerned with pleasing their partner. "As soon as a man has any kind of feelings for a partner—even on the level of wanting her to like him—a lot of that focus on his own satisfaction gets shifted to wanting to be good in her eyes," he says.

Some Men Are Incredibly Sensitive About Their Sexual Performance
Morgentaler has had patients whose sexual dysfunction were linked back to a single negative comment or bad experience. From buff, tough men breaking down in his office, to guys who were devastated when they found out their wife faked an orgasm, the cases have shown that some men's confidence and masculinity is deeply rooted in how they see themselves through the eyes of their sexual partners. This doesn't mean you should lie to a guy about being amazing in bed but Morgentaler suggests another takeaway: "If women want to know the single best thing to keep a relationship positive, I say that if a guy has done something good for you sexually, let him know. Even a simple 'that was great,' will do wonders."

Some Women Have a Higher Libido Than Men
Women today are more sexually liberated and more comfortable asking for what they want in bed, which is an overwhelmingly positive thing. But guys who are familiar with the stereotype that men have higher libidos than women are worried by it. "What I'm seeing much more now are men who come in and describe a relationship where their partner wants to have sex a lot more than they do," says Morgentaler. "It's not that their desire is so low, it's just that some women have a stronger libido. That's probably always been true, but culturally they were not expressing it as much as they do now." In fact, he has more men come into his office asking for help "keeping up" with the libidos of the women they're dating. Some men who can go one or two rounds in bed are seeking Viagra so they can go a third time—even when they have no actual erectile issues!