Kourtney Kardashian broke things off with Scott Disick earlier this summer, after he returned from Monte Carlo, where photos showed him uncomfortably close to Hollywood stylist Chloe Bartoli.

Now a new report says Scott Disick may have gotten the ultimate revenge against the Keeping Up With the Kardashians star.

Did Scott Disick really hook up with Kourtney Kardashian’s BFF?

“It was going on for several weeks,” a source says of Scott Disick and Kimberly Stewart, adding that the two were intimate the night of August 26, after her brother Sean’s 35th birthday party.

Exclusive: Scott Disick hooked up with Kourtney Kardashian's longtime friend! http://t.co/VH7biJwlPT pic.twitter.com/aRAjgZ0LuZ

— Us Weekly (@usweekly) September 11, 2015

Another source adds that when Scott Disick arrived at Hollywood lounge Warwick, he headed straight for rocker Rod Stewart’s 36-year-old daughter–yes, she’s that Kimberly Stewart.

“He immediately sat on the couch next to Kim and put his arm around her,” the second source says.

Kimberly Stewart attended The Buckley School in the Sherman Oaks neighborhood of L.A. with both Kim and Kourtney Kardashian. She is said to be the one who introduced Scott Disick to Kourtney Kardashian.

Scott Disick and Kimberly Stewart reportedly became involved after Kourtney Kardashian dumped Scott.

“Kimberly knew it was wrong, but couldn’t help herself,” one of the sources claims.

When friends starting gossiping about the fling, both put a stop to the hook ups. Kimberly Stewart, who stars in the E! reality show Stewarts and Hamiltons told Scott Disick she thought they should take a break–and he reportedly agreed.

Now Scott Disick fears he has wrecked any chance at all that he might have had for a reconciliation with Kourtney Kardashian.

“He feels like an a—hole,” says a source. “He was trying to get Kourtney back, but he is hoping she doesn’t find out. He’s kicking himself.”

Did Scott Disick commit the ULTIMATE betrayal?! Find out what he did to Kourtney: http://t.co/LzaR48uTc7 pic.twitter.com/ExvYidDNsO

— In Touch Weekly (@intouchweekly) September 11, 2015

Scott Disick is an a-hole–by most people’s accounts, anyway, and Kourtney Kardashian shouldn’t let him back into her life if he arrives at her door groveling on his knees. He has long caused her nothing but misery because he has no control over his partying ways. Even after a stint in rehab for his drinking problem he went right back to Vegas and started partying again.

Do you think Kourtney Kardashian will take Scott Disick back? Might she have been considering it before he allegedly hooked up with her BFF?