Mary Jo Eustace 'Respects' Son's 'Right to Express Himself' After Calling Her Out Online: Source

A source tells PEOPLE that Mary Jo Eustace continues to "respect" her son Jack McDermott's "right to express himself" after he called out his mom on Instagram this week, alleging she created a "strain on our family dynamic."

On Monday, Eustace's 24-year-old son with Dean McDermott claimed in a since-deleted Instagram post that she "spread information about my Dad, Step mom and my siblings" on the former couple's podcast Ex's & Uh-Ohs. Dean was married to Eustace until 2006 and is now married to Tori Spelling, with whom he shares five additional kids.

A source close to Eustace tells PEOPLE: "I'm sure it's very hurtful for Mary Jo to hear that her son is talking negatively about her. Unfortunately, the facts stand that it was Dean who was unfaithful and walked out on Mary Jo and the kids and then again unfaithful to Tori."

"It was Mary Jo that did 90 percent of the parenting and has been a loving and consistent parent. With that said, she respects Jack's right to express himself. And always will."

Mary Jo Eustace, Jack McDermott
Mary Jo Eustace, Jack McDermott

James Breeden/Shutterstock; Allen Berezovsky/WireImage

In his Instagram post, Jack began: "Since my parents divorce in 2006, I have rarely spoken out as I preferred to stay out of it. Unfortunately, due to my mothers recent decision to spread information about my Dad, Step mom and my siblings I am no longer able to stay silent."

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Mary Jo Eustace, Dean McDermott and Jack McDermott
Mary Jo Eustace, Dean McDermott and Jack McDermott

Charley Gallay/Getty; Dean McDermott/Instagram

RELATED: Dean McDermott's Son Jack Defends Dad and Tori Spelling, Says Mom Is Adding 'Strain' to Family

"About a week ago, my Dad made the decision to step away from his podcast with my mother 'Ex's & Uh-Ohs.' He chose to leave due to negative comments about our family and consistent attempts to malign his character. He also chose to leave due to the producer of the show betraying his trust and divulging private information," he continued.

"For 17 years my father has atoned for mistakes He's made in the past. He has grown so much as a person. Up until a week ago, our two families where [sic] living in harmony," wrote Jack. "With this podcast, it has driven a wedge between our two families and created a divide I am not capable of mending. Sadly, I'm not sure it can be."

"I ask that the information shared on 'Ex's & Uh-Ohs' be taken with a grain of salt," he said. "From my mother, I ask that you please respect me, and my blended family. Please avoid creating any additional strain on our family dynamic."

"These past few years have been nothing but peace and happiness, and I ask that we continue to try and keep it that way," Jack concluded.

Along with the message, Jack also included photos with Dean, Spelling and his siblings from a recent holiday photo shoot that featured the full family. Dean and Spelling share sons Liam, 15, Finn, 10, and Beau, 5, plus daughters Stella, 14, and Hattie, 11.