On Sunday, Scott Disick revealed during "Keeping Up with the Kardashians" that he is shocked by tabloid allegations that he's having an affair with girlfriend Kourtney Kardashian's stepsister, Kendall Jenner, 19.

Scott, 31, seemed genuinely upset by the rumors, and he was adamant they are false.

At the beginning of Sunday's episode, Disick had a conversation with Kim Kardashian in which he showed her a magazine cover on his smartphone that alleged his affair with Jenner. He laughed in disbelief. He told Kim that the unnamed magazine claimed he and Kendall were out together at night, but it was actually during the day. Plus, the picture of them had been Photoshopped.

It wasn't the only drama Disick had to cope with on Sunday's episode.

Disick, who flips houses on the side, asked Kourtney, 36, to fill in as interior designer on a project. Kourtney had plenty of ideas on how to improve the property, but her top-shelf tastes and extreme measures proved too much for Disick to handle.

In house flipping, the idea is to renovate the property to be improved and salable at the least expense possible. Kourtney wanted to knock down multiple walls, change hardware, change doors.

"I mean, by the time she gets done, I'll be losing money," Disick said.

Despite Disick explaining to her that moderation was needed, Kourtney continued to make interior design selections that were far from frugal.

"This chick is crazy, my designer over here," Scott said to a friend.

He also got annoyed that she wanted to go over interior design trends with him at 10 p.m.

It was a crazy episode. Khloe Kardashian, 30, decided to have stretch marks lasered off her butt, and Kylie Jenner, 17, finally admitted that she had fillers injected in her lips to plump them.

Watch "Keeping Up with the Kardashians" on Sundays at 9 p.m. ET on E!