The K ladies are good at everything... except for keeping their men in check!

Kourtney Kardashian has called it quits with Younes Bendjima after over a year of dating, but he's not wasting any time moving on! TMZ published pix of him all over Hooters waitress and former Justin Bieber fling Jordan Ozuna in Mexico today, and it's gotta sting for his ex.

The mother-of-three and the 26-year-old male model also unfollowed each other on Instagram, which is the modern day equivalent of announcing your breakup to the world.

They seemed happy when they vacationed for over a month in Italy with her kids in June, but apparently the romance went south shortly after that. Or perhaps Kourt got the heads up her man was fooling around behind her back and got the jump on dumping him to save face?

She's probably devestated, as multiple sources tell us she was planning her future with him.

An insider tells X17:
    "Kourt is undoubtedly heartbroken. She never thought she'd move on from Scott, and then she fell in love with Younes. Everybody thought he was too young for her, but she really believed they'd live happily ever after. That's the whole reason why she was even thinking of freezing her eggs and having more kids."

Here's the Kardashian clan's new enemy...