"He's moved on," a source told ET on Friday. "He's on the rebound. He's been going out on the town a lot since they split."
The source revealed that although the Secrets and Lies star has been out at least twice a week with friends, he's also been making plenty of time for his family, especially his 13-year-old son, Deacon, whom he shares with ex-wife Reese Witherspoon.
"They have a great bond," the source explained. "They spend quality time together. He's a good dad."
In addition to Deacon, Phillippe and Witherspoon also share a 17-year-old daughter, Ava. The Delaware native also fathered a daughter, 5-year-old Kailani, with Pitch Perfect actress Alexis Knapp.
Last April, Phillippe couldn't stop gushing over Slagter while chatting with Howard Stern on his SiriusXM radio show.
"She's awesome. When people see her they have these judgments because she could be a model, but she's about to graduate Stanford Law," he said at the time. "Also, what's great about it -- as you get older, certain issues become more important to you. I'm very involved in civil rights issues, and so to be with a woman who could actually make an impact in the legal realm, that's a beautiful thing."