'KUWTK': Scott Disick goes on rampage after hearing Kourtney Kardashian is dating: 'I've been really present'

Scott Disick and Kourtney Kardashian's tumultuous relationship took center stage on Sunday's new Keeping Up With the Kardashians.

Despite Scott's best efforts to walk the straight and narrow path of sobriety in his attempt to win back his ex-girlfriend and the mother of his children, things still managed to go south, quickly.

As the episode opened, Scott was sitting down with Kourtney's sisters, Kim Kardashian West and Khloe Kardashian, and the trio talked about what their recent family trip to Aspen, Colorado, meant when it came to Scott's attempts to get back together with Kourtney.

"Kourtney and I have been spending a lot more time together, so I decided to take her and the kids to Aspen, and she agreed to go. So for me that's a big thing," Scott said in a solo interview with the KUWTK camera.

WATCH: Scott Disick Says He Proposed to Kourtney Kardashian, But They 'Got Scared' and 'Never Spoke About It Again'

Scott also explained to Kim and Khloe that their Aspen getaway was the "first trip in a long time where we actually were a family, and it got to feel like the old days."

Scott went on to explain that he's been trying to stay health and be an attentive father to their three kids -- Mason, 7, Penelope, 4, and Reign, 2.

"I've been really present and I haven't been drinking," Scott said. "A year or so ago, I feel like there was a point where we didn't even speak or see each other, so this is good."

As the episode progressed, Scott joined Kim for a trip to Dubai, where the 36-year-old mother of two attended a makeup conference, while Scott made a publicity appearance at the grand opening of the city's Sugar Factory.

The night before his appearance, Scott heard through a friend of a friend that Kourtney was out on a date with a guy back in Los Angeles, which caused him to go on a tailspin.

WATCH: Scott Disick Admits Kourtney Kardashian Still Turns Him On, Says He'll 'Never Be Over Her'

Speaking with her friends at lunch, Kim opened up about Scott's battle to stay sober and healthy in an attempt to be a better person, and how that battle is made much harder when he hears about Kourtney moving on with her love life.

"The thing is, he's trying to win her back.... He's been doing amazing for months," Kim said, referring to Scott's successful stint in rehab and his subsequent clean living. "He said to me, 'I'm not even doing this for her. I'm doing this for me. I'm going to stay the course.' He fully has said that to me three times."

However, it becomes clear that the news has hit Scott harder than anyone would have guessed.

"This is probably the worst thing I could ever hear, ever," Scott said in a solo interview after trying and failing to keep a smile on his face as he shook hands with fans at the Sugar Factor opening.

"I don't think she realized a friend of my saw her. Of course I called her and asked, and she blatantly lied to me. It was somewhat heartbreaking," Scott continued. " I just didn't see things going this direction. I feel like everything I've been working so hard for is kind of done now."

WATCH: Kourtney Kardashian Rides Roller Coaster With Ex Scott Disick While Celebrating 38th Birthday

After the event, one of his friends invited him out for a night of partying, which the clearly distraught Scott accepted with enthusiasm.

The next day, Kim got a text from the hotel security that Scott had gotten drunk, and was still tipsy by midday. Kim quickly texted Kourtney the news of Scott's relapse.

Speaking with Khloe later that day, Kourtney said she doesn't get why Scott is so hung up on her and her love life, since they've been broken up for nearly two years.

"For years I was trying to be supportive, but letting him know in the meantime -- while he's showing his consistency -- that I have to live my life and make myself happy," Kourtney explained. "He has to take responsibility for his own actions."

When Kim and her entourage stopped by Scott's place in the morning, one of her friends discovered a woman's purse in his living room, and Kim became obsessed with the chance to catch him with a woman in his room.

WATCH: Kim Kardashian Looks for a 'Tramp' in Scott Disick's Hotel Room in Drama-Filled 'KUWTK'

"Something came over me, I was like, 'He has a girl hiding somewhere and we're gonna find her,'" Kim said in a solo interview.

Quietly, as Kim and her crew stormed around Scott's large suite, he admitted to a producer that there was, in fact, a girl hiding in his place, adding "This is going to be really awkward."

As Scott and his crew tried to convince Kim that they should all just head out, she loudly shouted, "Or do you think we should go bang down the bathroom door and see if some f**king whore is in there?"

Kim slammed on the bathroom door and demanded the woman inside open the door. When she finally did, Kim had nothing but vitriol for her.

"What the f**k are you doing here? You're such a whore! You're such a tramp. Get your s**t and get the f**k out of here... security will escort you the f**k out of here," Kim yelled at the girl as she walked out.

But before more on the situation could be revealed, the infamous KUWTK "To Be Continued" title card came up, leaving fans to find out how Scott deals with this new development when the next episode of KUWTKairs next Sunday at 9 p.m. ET/PT on E!

WATCH: Kourtney Kardashian and Scott Disick Are 'Back At It Again With the Co-Parenting Skills' in Hawaii