You used to think he was insatiable in the bedroom. Now? Not so much. If your husband’s sex drive has tanked, it can leave you feeling confused, concerned and maybe even hurt. Here, our experts unlock the secrets to the mysterious male libido and help you figure out what to do when he’s lost that loving feeling.

1. Male “Menopause”
It may be surprising to hear, but many health experts say that what menopause is to women, andropause is to men. The good news for our guys: It’s not as sudden or intense as the bodily changes women can sometimes face. As men age, it’s natural for them to experience a somewhat decreased sex drive, says Jeanne O’Connell, MD, medical director and cofounder of Sylvana Institute for Medical Aesthetics in Frederick, Maryland.

What to do? There’s always the little blue pill, but rushing to a prescription may not be the best approach. Bottom line, says Dr. O’Connell: Try not to take it personally if he used to want to tear off your clothes when you walked in the door and now he hardly notices the new skirt you’re wearing. The reason may simply be a biological one, not that he isn’t attracted to you. Instead of closing up, talk to him about his sexual feelings and needs—and yours.

2. Pornography
It’s a touchy subject among psychologists and sex therapists—some say that porn can fuel the passion in a relationship, while others think it can tear a loving relationship apart. What most experts agree on, however, is that when a man develops a pornography addiction, it can be devastating to a relationship.

“When porn becomes addictive,” says Les Parrott, PhD, a Seattle-based psychologist and the author of Crazy Good Sex, “a man relies on it to become stimulated instead of relying on his spouse.” He explains that the neurochemicals flooding a man’s brain during a porn fix (also called “eroto-chemicals” by psychologists) can create a cocktail in the body that researchers believe may be as addictive as cocaine.

The problem? “Studies have shown that porn fuels unrealistic expectations about what sex should be like,” says Dr. Parrott. “It makes men less satisfied with their partners.”

Do you suspect that your guy may be getting sexual gratification from pornography instead of you? “A woman should pay attention to that feeling, that instinct, and follow up on it,” says Dr. Parrott. Ask yourself: Is he spending more time alone in the basement on the computer? Is he not interested in physical intimacy the way he used to be? “When you’re thinking, ‘I wonder if that may be going on,’ chances are it may be. Listen to your gut.”

While a pornography addiction can be hard thing for a marriage to recover from, Dr. Parrott says you can heal and he can get help. “You can turn this around,” he says. “He needs to acknowledge the problem, and set up safeguards to prevent himself from falling into it again.”

3. Low Testosterone Levels
According to estimates, as many as 13.9 million American men have low testosterone, also known as hypogonadism, and it may be the reason he’s turning you down night after night.

How can you tell if your husband has this condition? In addition to a low libido, symptoms of low testosterone include decreased energy, low mood, fatigue, loss of muscle mass and even erectile dysfunction, says Abraham Morgentaler, MD, associate clinical professor of surgery at Harvard Medical School and a urologist at Beth Israel Deaconess Medical Center in Boston. According to Dr. Morgentaler, as many as 97 percent of men who have low testosterone levels report a negative impact on their sex lives. Fortunately, the condition is treatable.

4. Lack of Kissing and Hugging—from You
Did you kiss your husband good morning? Hug him before you left for work? Here’s the thing, says Raphael Darvish, MD, MBA, a physician with Concierge Medicine in Los Angeles: His disinterest in sex could be because you’re not showing him enough everyday affection. “Loss of libido in men often has little to do with medical causes and a lot to do with the women in their lives,” says Dr. Darvish. “Not feeling wanted and no or limited physical contact can really hurt a relationship.”

What can you do? Try a spontaneous hug, kiss or back rub, he says. It could have big payoffs for his happiness and your sex life.

5. An Undiagnosed Health Condition
Loss of sex drive for a man doesn’t just mean problems in the bedroom. His low libido could be a clue to other concerning health problems, says Phil Nguyen, MD, an erectile dysfunction expert with the Boston Medical Group. “The penis can be considered a barometer of overall health for men, and if there are problems in this area, it could be symptomatic of larger health issues such as diabetes, prostate cancer or heart disease,” he says.

While a loss of sex drive doesn’t always mean he has a health condition, it wouldn’t hurt to mention your concern to him so he can pass along any questions to his doctor.

6. Allergies
Sniffles, sneezes and coughs…oh my! Allergies just aren’t sexy. Now, a new study from researchers at the Cleveland Clinic confirms that his sneezing could be messing with your sex life. According to the study’s findings, as many as 83 percent of people who suffer from allergies—seasonal or otherwise—report a decline in sex drive and sexual satisfaction. The reason is simple: A runny nose and watery eyes definitely doesn’t help you get in the mood.

The lesson? If his allergies are getting worse, a trip to the doctor for a new prescription could cure them—and help your sex life, too.

7. The Economy
“Not tonight, honey, I’m worried about our stock portfolio.” Could his worries about your financial future really be interfering with his libido? Yes, says Eric Plasker, MD, author of The 100 Year Lifestyle. “Those under an extreme amount of stress often lose their sex drive, temporarily,” he says.

Clearly, you can’t remove the source of his stress or turn your investments from red to green on the stock charts, but you can encourage him to make simple changes that will boost his health, and his libido. For example, instead of dinner and a movie for your next date night, do something active together, suggests Dr. Plasker. “Exercise makes people feel better about themselves and may increase endorphins.” You can also make him a healthy, lowfat dinner. “Those who eat heavy, fattening, greasy or overly sugary foods may feel tired and sluggish, not sexy,” he adds.

8. Excessive Masturbation
Yes, masturbation can be an awkward thing to discuss with your husband. But if he’s masturbating too much, says Hilda Hutcherson, MD, an ob-gyn and the author of What Your Mother Never Told You About Sex, it may mean he’ll be less interested in sex with you. Here’s why, she says: “If a man is spending a lot of time masturbating, he can become accustomed to a higher, more intense level of sexual stimulation, which is stronger than he can get from the vagina. This can eventually make it hard for him to enjoy sex with you.”

What to do? Talk about it! Don’t let it be an isolating issue for the two of you, she says, and encourage him to turn to you when he’s in the mood.