Kourtney Kardashian, Scott Disick Relationship in Crisis?

Kourtney Kardashian and Scott Disick's relationship is reportedly in turmoil following new reports that his hard partying and wild antics have pushed the pair even further apart.

Kardashian, who recently began preparing for life as a single mom, is said to be so concerned about Disick's erratic behavior that she now refuses to leave him along with their newborn child, Penelope Scotland.

"Scott is never alone with Penelope because he is so irresponsible," one insider told RadarOnline.com. "Kourtney doesn't even like for him to hold [the baby] because she's afraid he'll drop her."

The source also explained that the pair is currently "the worst they've ever been," and it was allegedly Khloe Kardashian who informed the mother of two that Disick had returned to his old ways.

"[Disick's] on a downward spiral" and "[he's] more of a mess than I've ever seen him," the source went on.

Just days after Kardashian, 32, gave birth to Penelope, Disick reportedly flew out to Miami where he was spotted partying at LIV nightclub. Onlookers say that the reality TV personality was drunk and up to no good.

"Scott was hitting on Christina [Milian] all night. She kept ignoring him but he was acting like he just didn't get it. He just kept following her and pretty much begging her to party with him," a source told BOSSIP.com.

"Not only was Scott being really thirsty toward Christina, he was clearly drunk ... completely wasted," the source added.

Just days prior to reports of him hitting on pop singer Christina Milian, his criminal history was leaked to the media. Brittany Reichek, an alleged former friend of the 28-year-old, accused him of theft when he was younger, although her claims have never been verified by police.

Disick has previously been drunk and abusive toward Kardashian on their E! reality TV shows, and his extreme behavior continues to add friction to their already strained relationship. This has prompted reports that the reality star may finally leave him.

"[Kourtney] doesn't need Scott. Since Kourtney's become a mother, her priorities have changed, and Scott hasn't shared her love for being a parent," a source told Life & Style magazine.

"Scott's totally out of control and a loose cannon, he's doing whatever he wants to do," another source explained adding that "their relationship has always been so up and down and he's definitely back to his old ways."