"Partying and making out with different girls publicly, isn't exactly the best behavior when you are a dad," a source tells PEOPLE

Kourtney Kardashian isn’t pleased with Scott Disick‘s recent behavior, and “wants him to make good choices” for the sake of their three children.

In the two days since Kourtney and Disick wrapped a family weekend trip to Costa Rica with their kids — Mason, 7, Penelope 4, and Reign, 2 — Kris Jenner, Corey Gamble, Khloé Kardashian, Kylie Jenner and her beau, Tyga (as well as his son, King), and Kim Kardashian West and her two children — North, 3, and Saint, 1 — the father of three jetted to Miami, Florida, where he has spent his time cuddling up poolside with models.

“Scott hung out with a model at his hotel pool. They were affectionate. Scott kept ordering drinks for them,” a source told PEOPLE about Disick, who arrived in Miami on Sunday. “He seemed to have a great time. It was only a one day thing.”

But on Tuesday, Disick was again spotted at the Setai Hotel pool, this time with a blonde. “Scott is spending the day with a blonde girl,” the source said. “He is again by the pool and seems to have a good time.”

Although Disick made a surprise appearance at the family’s tropical vacation — a source previously told PEOPLE that “Kourtney disinvited him” after he partied at Sundance and was spotted with a “very Kendall Jenner-like” brunette — and documented their excursions on social media, tensions between the parents of three arose before they departed for Costa Rica.

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“Kourtney hasn’t been happy with Scott for weeks. It has nothing to do with what he is doing in Miami right now,” the source said. “She just doesn’t like when he parties. He is an irresponsible dad when he parties.”

According to a Keeping Up with the Kardashians source, “Kourtney returned to L.A. on Monday with the kids. She is not happy with Scott. She allowed him to come to Costa Rica for a couple of days so he could have fun with the kids. Scott’s behavior is again getting out of control. He is partying a lot.”

The pair ended their nine-year relationship in July 2015 after he was spotted cozying up to another woman. But in the year since the duo called it quits, they have remained committed to trying to make it work as they continue to co-parent their three children.

“Kourtney just wants him to make good choices because of their kids,” the source said. “Partying and making out with different girls publicly isn’t exactly the best behavior when you are a dad.”