Mary Cosby is finally opening up about one of the most talked-about parts of her past. On a recent episode of the “Real Housewives of Salt Lake City,” the reality star shared how her marriage to her step-grandfather, Robert Cosby Sr., came to be. She explained that the decision followed her grandmother’s dying wish — and admitted it was an unusual situation for both of them.
Mary Cosby Explains Her Unconventional Marriage
While walking through the newly renovated Faith Temple Pentecostal Church with her cousin and contractor “Big Joe” on season 6, episode 4 of RHOSLC, Mary reflected on the church’s history and how she unexpectedly stepped into the role of first lady.
She shared that her grandmother, Rosemary “Mama” Cosby, founded the church and called her back to faith when she was young. “Because that’s what happened to me,” Mary said. “When I was younger, I remember Mama called me and she was like, ‘Mary, I think it’s time for you to come back and be saved and get in church.’ And I was like, ‘OK.’ And because of her, I am everything I am.”
To take over the church after Rosemary’s death in 1997, Mary said she was instructed to marry her grandmother’s second husband, Robert Sr., who served as bishop. “That was odd to both of us,” she admitted. “Marry me? He obeyed what Mama wanted. He wasn’t trying to do anything extra.”
Mary expressed excitement about returning to the church as it reopens, especially to support her son, Robert Cosby Jr., following his rehab journey. “Some prayer” could “help” him, she told Big Joe.
The RHOSLC Star Opens Up About the ‘Hurtful’ Estrangement From Her Mother
Mary’s path to leadership wasn’t universally accepted — including by her own mother, Rosalind. When Big Joe mentioned that Mary had “battled the storm,” she responded, “For some reason, my mom thought she was supposed to take everything over. How? … My mom, she wanted her way, and she couldn’t get her way.”
Mary explained in a confessional that her grandmother’s wishes were clear, but her mother attempted to take control after Rosemary’s death. “Once my grandmother passed, my mom just started trying to take over everything. And things got bad,” she said.
Mary and her cousin recalled that Rosalind was “escorted out” by police during a service. The two remained estranged until Rosalind’s death in January 2025. “And the fact that it’s full circle now and she’s gone, I don’t know how I feel about that,” Mary told her cousin. “It’s like a roller coaster. It hurts. But it’s also a chapter that’s closed. … I feel like it was a storm or a battle that I had been in for all those years.”
Through tears, Mary shared that her mother spread “lies” in the media about her and Robert Sr. “When my mom walked out of my life, I felt that absence,” she said. “But my mom didn’t wanna speak to me, and so I gave her what she wanted. And when she left the earth a few months ago, it almost felt like it was actually official, because it became a whole bigger real hurtful reality.”
Robert Cosby Sr.’s Role in Mary Cosby’s Life Today
Mary and Robert Sr. married in September 1998 and remain together. Earlier in season 6, she credited him with supporting their son’s recovery.
“I didn’t have a support system with him, I just had Robert Sr. I just have one,” she said during the cast’s RV camping trip. “I couldn’t have done it without Robert Sr. I couldn’t have done it at all.”
After Robert Jr. completed rehab, Mary and Robert Sr. sat him down for a serious talk. “Robert Sr. told him, ‘We cannot babysit you. You have the tools, and you know what you need to do,’” Mary recalled. “We, like, made a pact that we would take one day at a time, and we’re letting him figure it out. And that’s how I deal with him.”
Fans can catch Mary Cosby in new episodes of RHOSLC, Tuesday nights on Bravo.
