Kourtney Kardashian plotted her revenge after ex-boyfriend Scott Disick brought a girl to the family vacation in Costa Rica on Sunday's episode of Keeping Up With The Kardashians.
Scott, 33, earlier cuddled up to Kourtney 38, during the Kardashian family getaway before secretly bringing a girl to meet up with him.
Scott's secret tryst was uncovered when the visitor – a girl named Chelsea – had to get past security to access his hotel room.
After being told the news by sisters Kim and Khloe, Kourtney said: 'I don't understand why he would even think to invite somebody. It's hurtful and disrespectful.'
'Are you OK?' her mother Kris Jenner asked.
'Yeah. I'm just thinking about all the guys I'm going to f*** when I get home,' Kourtney quipped.
Scott's Costa Rica liaison came after he found himself under fire for inviting a girl back to his room during his trip to Dubai with Kim.
Viewers saw Kim fly into a rage at the unnamed girl and ask security to throw her out of their luxury hotel room.
While the girl cowered in the bathroom, she screamed: 'What the f*** are you doing here? Seriously, you're just like a f***ing whore. Such a tramp. Get your s*** and get the f*** out of here.'
She added: 'Groupie, get your s*** and security will escort you the f*** out of here.'
'I spoke to Kourtney about it. Kourtney is like ''I have no intentions of us working things out really. I want to live my life and you live yours'',' Scott told Kim.
'I'm not even trying to play games, but I'm not going to lie, it's hard to f***ing sleep at night. It puts me in a hard position. I don't even want to be doing half the s*** but I don't know what else to do with my time to take my mind off it.'
Kim said: 'I don't want to be in the middle of it.'
Scott told her: 'She never, ever gives me any kind of pat on the back for anything. The only time I hear from her is if it's something negative.'
Back in LA, Kim told Kourtney that Scott had been 'out of it' in Dubai but assured her he was not going to drink when he got home.
Kim said: 'I do think where you go wrong is you go to Cabo with him, you go to Aspen with him… and you'll see a movie with him. To be honest I feel if Scott got his s*** together you would be with him. It is your baby daddy of three.'
'Yeah, but it is his fault we're not together,' Kourtney said.
Despite his antics in Dubai, Kourtney allowed Scott to come on the family trip to Costa Rica – much to the confusion of her sisters.
'They're not together but she leads him on,' Khloe told Kim. 'Going to Aspen together through New Years is strange. I said ''you're giving him false hope. I understand why he thinks you guys are together. I think you're together''.'
Instead of staying at the family villa in Costa Rica, Scott checked himself into a hotel and told Corey Gamble it was because he liked his own space.
He told the camera: 'I only really get lonely and start to annoy myself more that the girl I used to be with is down the hallway and I'm not sleeping with her, what has my life come to? I don't really feel like there's any reason for me to sleep under the same roof.'
He then was showing sitting next to Kourtney in bed and kissing her as Kim and Khloe looked on.
'It ain't happening,' Kourtney told him.