Demi Lovato Was 'Shocked' When She Discovered Max Ehrich's Intentions 'Weren't Genuine': Source

Demi Lovato has learned the painful truth about her ex-fiancé Max Ehrich's intentions for their whirlwind relationship.

Just hours after PEOPLE exclusively confirmed that Lovato, 28, and Ehrich, 29, had made the ″tough decision″ to call off their engagement and go their ″separate ways,″ the singer appeared on her Instagram Story — notably without her engagement ring.

The pop star also seemingly threw subtle shade at her now-ex by zooming in on the words displayed on her T-shirt which read, ″Dogs over people.″

Multiple sources say that Lovato and The Young and the Restless alum — who got engaged in Malibu on July 22 just four months after they started dating — were having ″conflicts″ over the past few weeks.

One insider close to Lovato says, "It was very hurtful to Demi when she realized that Max's intentions weren't genuine. The source adds, ″Breaking off the engagement was not an easy decision."

RELATED: Demi Lovato's Ex Max Ehrich Says He Found Out About Their Relationship Status 'Through a Tabloid'

″Demi and Max were basically together 24/7 for months,″ says another insider about the early stages of the pair's relationship.

″They lived in a bubble with zero stress and everything was just fun,″ the source continues.

But things quickly began to change when Ehrich headed from L.A. to Atlanta to film a movie. ″Max shot up in fame, and it's been hard,″ says the insider. ″He got wrapped up in [Hollywood].″

When Ehrich's previous tweets professing his love for Lovato's former best friend Selena Gomez, 28, resurfaced on Twitter earlier this month, Lovato publicly supported him. She even slammed the posts as ″fake″ in her Sept. 13 Instagram Story.

RELATED: Max Ehrich Shares First Social Media Post Following News of Split from Demi Lovato

Soon after, the singer began to believe that Ehrich was really just ″trying to further his career by using her name behind her back,″ according to the insider.

With her loved ones' support, Lovato broke off the engagement. The star has been open about her battles with mental health and addiction, but she is ″doing okay,″ the source says adding that ″[the breakup] is a good thing.″

Sadly an insider says, ″It was hard for Demi to admit she made a mistake when it came to Max."

For more on Lovato and Ehrich's short-lived engagement, pick up the latest issue of PEOPLE, on newsstands Friday.