Megan Fox Is 'Having a Hard Time Trusting' MGK but They're 'Still Working on Their Issues': Sources

"Only time will tell if they get back together properly," a source tells PEOPLE after Megan Fox hinted at a potential breakup with fiancé Machine Gun Kelly last month

Megan Fox; Machine Gun Kelly. Photo: Kevin Mazur/Getty Images for The Recording Academy; Ethan Miller/Getty Images

Megan Fox and fiancé Machine Gun Kelly are working on their relationship, a source tells PEOPLE.

After the actress hinted at a potential breakup last month, a source close to the couple says that they are "in therapy" but Fox, 36, is "having a hard time trusting" MGK, 32, following rumors of his infidelity, which she has since denied.

"This is really boiling down to not working," the source says. "There have been points where they haven't been speaking, it's been that bad."

Another insider explains that they are in contact and "still working on their issues," adding: "Only time will tell if they get back together properly, but it looks pretty unlikely right now."

Reps for Fox and Kelly have not responded to multiple requests from PEOPLE.

The insider notes that the couple has "always had kind of a tumultuous relationship," which has "never been easy, it's always been very up and down."

Megan Fox and Machine Gun Kelly. Vivien Killilea/Getty for Universal Music Group for Brands

"Megan was thrilled when they got engaged, though. She really loves him," the insider continues. "She was never one to casually date, so she put her whole heart into their relationship. She isn't happy now, though. She took her engagement ring off a while ago, and it's not back on."

Fox notably appeared without the engagement ring on her finger when she flew solo at the Vanity Fair Oscars afterparty this month.

The couple appeared to hit a rough patch last month when Fox completely deactivated her Instagram account shortly after hinting at a potential breakup between her and her musician fiancé by deleting all traces of him from the profile.

At the time, she uploaded a series of photos of herself and a video of an envelope being burned in a fire pit and captioned that post with lyrics from Beyoncé's "Pray You Catch Me" from her 2016 album Lemonade, writing, "You can taste the dishonesty / It's all over your breath."

RELATED VIDEO: Megan Fox and MGK Are 'Not Giving Up on Their Relationship' but She Is 'Still Upset': Source

Upon her return to the platform, Fox shared a since-deleted post saying there was no cheating involved in their relationship troubles. As of Friday, the actress's Instagram still features no posts.

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A source told PEOPLE on March 14 that Fox and MGK are "still trying to sort through things, but most of their friends think it is likely over," adding: "They're just not ready to totally call it yet."

Fox and Kelly first met on the set of the indie thriller Midnight in the Switchgrass in March 2020. The musician proposed to Fox in January 2022.