The man the Kardashian clan calls "Lord Disick" has been "living like a king" -- and it's all coming out of his baby mama Kourtney Kardashian's coffers, causing further tension in their already rocky relationship.

Scott Disick has been "spending like he's Jay Z or something, while he completely cast Kourtney aside," a family insider tells InTouch.

"How can she not feel used?"

The dashing male socialite's made $2 million on the family's reality shows, but spent every last penny on amenities like fancy cars, extended stays at posh hotels, private jet rides and gold bling, the insider told the magazine.

"All of the money he has is because of her."

As for Kourtney, she's a lot more conservative with her cash, despite her family's gold-plated