The country star reveals his booze abuse got so bad he was chugging alcohol before waking up his daughters when they were kids.
Sober since 2008, he recalls the moment he hit rock bottom and asked his wife for help.
"I remember a moment when I was getting out of bed and going to the liquor cabinet and taking a big shot at eight in the morning and thinking, I have to wake the kids up," he tells Esquire magazine.
"I went straight to my wife and said, 'This is where I'm at.' I was scared. She just grabbed me and hugged me and changed my life.
"My wife always says, 'You're not scared of anything.' I say, 'Ehhh, one thing. I'm looking at it right now.' "
"I didn't know love could feel so good. Was it an emotion? Was it a lifestyle? Was it an imaginary thing? But love is all of those things."
McGraw also tells the magazine he and Faith have a volatile relationship because they insist expressing anger is healthy.
"Love is being angry. Love is not talking for a day. Love is getting in each other's face. Love is accepting that I'm wrong. Love is a 360-degree thing. It's not linear," McGraw explains. "They always say you're not supposed to fight in front of your kids. Everybody fights in front of their kids. That's part of the deal."
The policy seems to work - Tim and Faith will celebrate their 25th wedding anniversary in October (21).