Thorne and Sulkin split last August after more than a year together
Credit: Alberto E. Rodriguez/WireImage for MTV Communications

Things are heating up between Bella Thorne and ex-boyfriend Gregg Sulkin.

Since returning from the Cannes Film Festival in France, where she was spotted getting frisky with Scott Disick, Thorne has been spending time with her former beau, including soaking up the sun together on board a pool float.

“Bella and Gregg had a difficult relationship when they were together. She felt like he was too controlling and that’s part of why they broke up, but they’ve been talking for a little while and going back and forth,” a source close to Thorne, 19, tells PEOPLE.

“After hooking up with Scott and feeling like a total fool, she realized she and Gregg had something more special. She started hitting him up after she got back,” says the source.

Last August, Thorne and Sulkin, 25, exclusively revealed in a joint statement to PEOPLE that they were ending their relationship after more than a year together, stating, “Our schedules made seeing each other difficult.”

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But since their split and the months spent apart from one another, the amicable exes are now spending time together once again. On Friday, the actor headed to Cocina Condesa for dinner in Studio City with a group of friends (where they snacked on guacamole, tacos and drank margarita cocktails) to celebrate his 25th birthday before partying at Avenue LA in Hollywood.

“Gregg’s missed her too, though he’s still playing around and hanging out with other girls,” the source says about the British actor. “They spent his birthday together and they’re rekindling things and hooking up.”

Since the duo’s split last summer, Thorne has been tied to Charlie Puth, Tyler Posey, and most recently, 33-year-old Disick. Although the former Disney channel actress and the Keeping Up with the Kardashians star jetted off to Cannes together, Thorne feels “played” by Disick, who got handsy with a bevy of beautiful women — in addition to her — in Cannes.

“She feels like an idiot and like she got totally played,” the source adds. “She thought she could be that cool party girl, but now she’s feeling super dumb and vulnerable. Her natural instinct is to run to her first love.”

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Romance rumors surrounding Thorne and Disick sparked earlier this month when they stepped out for an evening together in Los Angeles, first dining at hotspot Catch and then moving on to The Peppermint Club.

But despite their chemistry, a source said that Thorne’s fling with Disick wasn’t initially serious.

“She’s just being young and having fun and doesn’t really care what people think or what their opinions are,” a source told PEOPLE. “She also knows that Scott is a huge playboy so she isn’t getting too invested. Basically, she’s being Bella and no one is going to change that.”