Elizabeth Vargas on How She Hit Rock Bottom When She Got Drunk on Her Son's 8th Birthday

On the day of her son Sam's 8th birthday in August 2014, Elizabeth Vargas planned to bake a vanilla coconut cake – his favorite. Instead, what should have been a day of celebration took a dark turn when the 20/20 anchor ended up in a detox facility.

In her new memoir Between Breaths (out Sept. 13), Vargas opens up about her battle with alcohol addiction and the day she relapsed for the last time.

While on her first vacation as a single mom Vargas was still reeling from the recent split with her husband Marc Cohn when she decided to drink the day her son turned 8, ruining his birthday.

Her brother and sister took her to a detox center in Pasadena, California.



"There was so much happening in those first few months when I was home," she recalls. "Really painful, public stuff. I think I was kind of in shock."

That trip wasn't her first time in a recovery center. She first checked in to rehab for alcohol abuse in November 2013.

But, Vargas now tells PEOPLE in an interview for the magazine's latest issue: "Rehab isn't what finally got me sober. It was nearly losing everything and finally seeing that whatever benefit I thought alcohol gave me was outweighed by what it would cost me."
• For more on Elizabeth Vargas and an excerpt from her memoir, pick up the new issue of PEOPLE, on newsstands Friday

She explains that her alcoholism was a well-kept secret until "it all blew up in my face." Vargas, whose drink of choice was Chardonnay, says she drank to ease her anxiety and to gain confidence – which may seem like a surprising problem for a successful news anchor. While the alcohol numbed her anxiety, it also blurred the good moments.

"I was in a little glass and everything was kept very far removed," says Vargas. During her drinking days, she couldn't enjoy small moments with her sons, like encouraging them to read a book during summer vacations.

"You're removing the capacity to be present, not just in the bad moments," she says. "You're numbing the good feelings. You're numbing everything. It's profoundly selfish."

Now that Vargas is sober, she is telling her story to help others. She says she wants to teach people that alcoholism is a disease – not something to be stigmatized.

"[Alcoholism] is not a matter of self-discipline. It's not even a character flaw. I would not hesitate for a nanosecond to step in front of a bullet, to do anything to give my life for my children," Vargas says. "I would kill for my children. And I couldn't stop drinking for my children."

As she continues to share her story with the public, she knows her sons will have questions. Vargas says that even though her sons didn't see her at her worst, "they saw enough." She's had many conversations with her boys. They all started with "I'm sorry."

"You can't make excuses," she tells PEOPLE. "You have to own what you did."