"It's more complicated than just fighting over a guy," a source tells PEOPLE exclusively. "Mandy and Selena have had their ups and down before."

Eagle-eyed fans noticed Selena Gomez and her mom Mandy Teefey unfollowed each other this week on Instagram, but a source close to the family tells PEOPLE exclusively their recent estrangement is not just because of the singer’s reunion with Justin Bieber.

“It’s more complicated than just fighting over a guy,” says the source. “Mandy and Selena have had their ups and down before. This isn’t the first time.”

After splitting from The Weeknd (né Abel Tesfaye) in October, Gomez, 25, began spending time with the “Sorry” singer, 23, whom she first began dating in 2010.

Mandy Teefey,Selena Gomez
Credit: Steve Cohn/Invision for Netflix/AP

Multiple sources previously told PEOPLE Gomez’s family was concerned about the on-again romance and that Bieber was determined to show her loved ones he had matured.

An insider confirmed earlier this week that Teefey, 41, had voluntarily sought treatment at a hospital in L.A. but dismissed a report that it was because of an argument with her daughter over Bieber. “It’s been a stressful time for Mandy and she made the decision herself to go to the hospital and make sure everything was okay,” said the insider.

2012 Vanity Fair Oscar Party Hosted By Graydon Carter - Roaming Arrivals
Mandy Teefey and Selena Gomez in 2012
| Credit: Christopher Polk/VF12/Getty

Though Gomez and Teefey aren’t on speaking terms currently, Gomez “also wants to give her mom some space,” adds the source close to the family. “When they fight, they fight hard. But when they love, they also love hard.”

“Selena’s mom is still not happy about Justin,” adds a Bieber source. “It’s definitely causing some family conflicts. It’s been hard on Selena. She really believes Justin has changed and wishes her family would trust her.”

Teefey — who produced Netflix’s hit series 13 Reasons Why with Gomez — shared an emotional Instagram post on Monday to remember Scarlett, the daughter she lost to miscarriage in 2011.

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“A moms [sic] love for their children is pretty fierce. In order of my girls, Selena, Scarlett and Gracie. Family is what matters, blood or not, #family13 made me smile and feel loved when so needed and they didn’t know,” she wrote in the caption.