One of the worst-kept secrets in Hollywood is that Jessica Simpson has long struggled with drinking. And after she was spotted stumbling out of a restaurant on Sept. 19 — with one eyewitness calling her a “mess” — In Touch has exclusively learned the extent of the mother-of-two’s issue with alcohol. “Jessica has a problem,” a source tells In Touch exclusively — making it clear that it’s not a new one.

According to a friend, she has been known to mix her anti-anxiety medication with alcohol, and her bad habit has only gotten worse in the wake of her father’s cancer diagnosis. “It’s been occurring on a frequent basis lately,” the friend tells In Touch. “The combination [of alcohol and medication] makes her loopy and disoriented.” See Jessica’s rough night for yourself in the video below!

Understandably, Jessica’s loved ones — including her husband, Eric Johnson — are worried about her downward spiral. But apparently, bickering with her hubby is part of her rapport. “They’ll fight about Jessica’s drinking for a few days and then apologize to each other until it happens again,” the friend says. While he once tried to plan an intervention for his problematic wife, “Eric just deals with it now,” the friend says. “Of course he’s embarrassed, but there isn’t much he can do. Jessica can be really stubborn and if she doesn’t want to do something, no one can make her.”

Jessica’s erratic behavior has become somewhat normal for her friends and fans. Two years prior, she made headlines when she appeared on the Home Shopping Network and appeared to be slurring her words. A rep for HSN reassured everyone she was sober, but many people weren’t buying it.

And now, it appears she has no intentions of changing. The friend adds, “Her behavior has become the new normal.”

For more on this, pick up the latest issue of In Touch — and for more exclusive content sign up for our newsletter!

Have a tip? Send it to us! Email In Touch at contact@intouchweekly.com.