EXCLUSIVE: Kourtney Kardashian Is Dating Again, 'She's the Happiest She's Been in a Really Long Time'

Kourtney Kardashian is moving on and moving up!

After a tumultuous 2015 that included a tough breakup from longtime partner Scott Disick, a Kardashian source tells ET that the reality star is getting on with her life.

"Kourtney is 100% over Scott," the source reveals. "Not in a hateful way at all, but she has completely moved o

What's more, the 36-year-old mother of three is really happy!

"She is the happiest she's been in a really long time -- since probably before Mason was born," the source explains. "When she had him, she really became introverted and only wanted to stay home with the kids."

"This breakup has really showed her that she needs to focus on herself," the source adds. "She's spending a lot of time with her girlfriends, is planning dinners and nights out. She's happy and glowing."

Not to mention getting back out there!

"[Kourtney] is dating," the source reveals. "No one special, but she is putting herself out there and is open to set-ups. She's not pushing it though."

With three kids -- 6-year-old Mason, 3-year-old Penelope, and 13-month-old Reign -- the source tells ET that Kourtney "knows she's done having kids," adding that they are still the top priority for her and Scott.

"Kourtney and Scott will always have a cordial relationship for the kids," the source says. "They are filming now, so any time they're together, it's for the show."

"Her kids are her first priority. She is very protective of them," the source adds.

The change in outlook is evident in Kourtney, who recently revealed in a text exchange with sister Khloe that she has got her "swagger back."

Taking care of herself is also the main theme of Kourtney's New Year's resolutions, which included "to live more in the present and less on [her] phone," "to continue on the workout mission that [she] started this year," "to continue to straighten [her] relationship with Jesus," and to "refocus [her] priorities, making sure that [she] is high on the list (children, God, me, family above all else...)."

Meanwhile, despite some recent positive developments for Scott -- such as purchasing a $5.96 million house near Kim and Kanye's home -- our source says "Scott is still in a dark place," adding, "The rumors of Kourtney and Justin Bieber really threw him off. He wasn't expecting it."

Scott also recently started seeing Swedish model Lina Sandberg, which our source says is "just a fling."