We all want a woman who can enjoy rugby and beer with the guys, but what happens when she becomes too friendly? It might make it harder to get it up, according to a new University of Chicago study.

Men were likely to report erectile dysfunction when his partner had more contact with his friends than he did—46 percent of men with extra-friendly partners had ED, compared to 33 percent of guys in the opposite situation.

Sexual dysfunction is often associated with physical factors like heart disease, but it can also be psychological, experts say.

“Masculinity is associated with control and independence,” says Benjamin Cornwell, Ph.D., professor at Cornell University, and author of the study. “Having a partner that intrudes on your relationships can make you feel less independent and ‘in control’ of your social life, causing anxiety and ultimately, sexual dysfunction.”

Researchers examined almost 700 men from the ages of 57 to 85, but believe this could affect anyone—it’s just that an older population is more prone to ED in the first place.

No matter what age you are, it’s important to have a life outside of your relationship. Not having an independent social life can reduce your self-esteem and increase your risk of anxiety and depression—all of which are linked to erectile dysfunction, explains Cornwell.

“Plan pub nights with your friends,” he says. “But be open with your partner and explain that it’s ‘guys’ night.’ ” That way, you’re not trying to make plans behind her back. Don’t worry: Every woman understands the value of “girls’ night,” so she’ll understand—or at least thank you when you try one of these 33 red-hot sex tips when you come back home.