Scott Disick has a confession: he hasn't kept his promise to remain sober.
In a sneak peek from Sunday's all-new episode of Keeping Up With the Kardashians, Disick, 28, tells girlfriend Kourtney Kardashian that he "didn't lie, but I kind of kept some of the truth from you about that time when I went with all the boys to Vegas."
"I didn't get out of control," he tells her. "It's nothing crazy, but sitting here in Tahiti makes me think I wouldn't mind having a drink or two because I believe that I'm in a place that I could have a drink or two responsibly and not get crazy."
"It's hard for me to trust you because of everything's that gone on," she explains, "and I don't want it to get back to that place."
Keeping Up With the Kardashians airs Sunday at 10 p.m. EST on the E! Network.