Back on the market, Kourt?

Kourtney Kardashian was out and about running errands with son Mason yesterday in Calabasas, and the reality star looked pretty glum on the outing. The reason we think she was in a bad mood? Her breakup with boy toy Younes Bendjima!

The reality star put the breaks on her relationship with the 23-year-old model after their romantic trip to Cannes, and even though she's the one that ended things, she's probably pretty lonely being single.

"Kourtney broke Younes' heart. While they were in Cannes he told her that he was falling in love with her, but she just wasn’t feeling the same way. She loved the sex but she was not able to give him what he really wanted, which was a serious relationship," a source dished to Radar.

It seems she was only hooking up with the hunk to get under Scott Disick's skin.

"When Kourtney brought Younes with her it was basically to make Scott jealous — and it worked! But she also realized that the age gap between them was just too much and she could not relate to him. Kourtney’s friends just really want her to settle down with a guy her own age and someone who has his own money," the source added.

We wonder what hot young thing she's going to go after next?