The pair is rumored to have begun dating in March and became engaged in July. Just last week, Fox News confirmed that their engagement had ended.
Since then, Ehrich, 29, has claimed on Instagram that Lovato, 28, didn't inform him of the breakup, but that he learned the news from a tabloid.
He followed that claim with several social media posts, per E! News, suggesting he was being "bullied" by the signer's fans.
"Please stop trying to thank you, next... Me," he said in reference to the popular Ariana Grande hit. "... For I'm just a human being who has to go to work tomorrow AM where there are families with kids relying on me. Thanks. God bless."
An insider told the outlet that Ehrich "is lying" about how he discovered the news, and explained that Demi informed him of the breakup before the press caught wind.
The posts reportedly haven't gone over well with the "Anyone" singer, according to a source that spoke to the outlet.
"Demi wants no contact with Max at this point," said the insider. "She is completely embarrassed at the way he's been acting and putting their relationship on blast via social media. She wants nothing to do with him."
Additionally, the source claims that Ehrich is "in denial" about the end of their engagement and has "tried to reach out" to the singer, but she finds his behavior "worrying" because she "does not want the situation to escalate."
"Demi is completely done and doesn't want to see him again at this point," the source said. "She can't believe she fell into his trap and is really upset over it."
Lovato hasn't spoken publically about the break up yet, but has been spending time with loved ones, according to the source.
"She's been spending a lot of time with her family and friends to help heal from this and they are all keeping her occupied and rallying around her," they said.
A source told People magazine that they broke up to focus on "their respective careers," but citing a source, E! reports that Lovato "didn't know who Max truly was and didn't think he had good intentions."
Reps for Ehrich did not immediately respond to Fox News' request for comment.