"He stopped drinking cold turkey—and promised he won't drink again until after Kourtney gives birth," the source tells Us. "Scott knew he had hit rock bottom."
The scary incident became a wake-up call for the 31-year-old, who is expecting baby No. 3 with Kardashian, 35, in December. The longtime couple are already parents to son Mason, 4, and daughter Penelope, 2.
"[Kourtney] told him that was the last straw," according to the insider.
As previously reported, Disick has had a difficult time since losing both his parents within the past year. "[He] went through a dark place," a source told Us, but "is doing great now."
For more on Disick and Kardashian's relationship, watch this week's Hot Stuff video as explained by Us Weekly's Entertainment Director Ian Drew and special guest, Bravo's Jersey Belle star Jaime Primak-Sullivan.