5 Shocking Secrets Inside Mary Cosby's Controversial Marriage To Her Step-Grandfather, Robert Sr.

The marriage of Mary Cosby and her husband, Robert C. Cosby Sr., remains one of the most controversial and talked-about relationships in reality television history. The unique union, which stems from a provision tied to a multi-million-dollar inheritance, continues to generate explosive headlines and dramatic family fallout well into late 2025.

As of late December 2025, the couple, known for their roles on The Real Housewives of Salt Lake City (RHOSLC), is navigating renewed scrutiny following recent family legal battles and ongoing controversy surrounding their Utah-based ministry, the Faith Temple Pentecostal Church. This deep dive uncovers the full, shocking history and the latest updates on the couple's unconventional life.

Robert C. Cosby Sr.: Biography and Role in the Cosby Empire

Robert C. Cosby Sr. is the husband of reality star and First Lady Mary Cosby, but his primary role is as a Bishop and spiritual leader. His life story is inextricably linked to the history of the Faith Temple Pentecostal Church, a ministry founded by his late wife, Rosemary "Mama" Redmon Cosby.

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• Full Name: Robert C. Cosby Sr.
• Primary Role: Bishop and Co-Pastor of Faith Temple Pentecostal Church in Salt Lake City, Utah.
• First Marriage: Married Rosemary "Mama" Redmon Cosby (Mary’s maternal grandmother) in the late 1960s. The age difference between Robert Sr. and Rosemary was reportedly 20 years.
• Second Marriage: Married Mary Martha Cosby (Rosemary’s granddaughter) in 1998.
• Child: He shares one son, Robert Cosby Jr., with Mary Cosby.
• Controversies: The church has faced allegations of being a cult, and Robert Sr. has been involved in the legal and financial complexities surrounding the church’s assets and Mary's inheritance.

Robert Sr. is known for his reserved demeanor on RHOSLC, often appearing as a grounding force for his eccentric wife. However, his quiet presence belies his central role in one of the most bizarre and compelling family sagas in the reality TV landscape.

The Inherited Marriage: How Mary Married Her Step-Grandfather

The foundation of Mary and Robert Sr.'s relationship is the single biggest source of public fascination and controversy. Their 1998 marriage was the result of a dying wish—or a legal provision—from Mary's grandmother, Rosemary "Mama" Cosby.

1. The Grandmother’s Will and the Church Succession

Rosemary Cosby, the founder of the Faith Temple Pentecostal Church, was a powerful and influential figure. Upon her death, she allegedly expressed a wish, which Mary claims was a provision in her will, that Mary should marry Robert Sr. to inherit the church and its associated multi-million-dollar assets.

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2. The Age Gap and Step-Grandfather Status

When they married, Mary was 24, and Robert Sr. was in his 40s. The relationship is considered incestuous by some critics because Robert Sr. was Mary's step-grandfather, having been married to her grandmother for decades. The marriage was reportedly necessary to keep the church's assets within the family line and under the leadership of a Cosby.

3. The 'True Love' Counter-Narrative

While Mary has consistently maintained the marriage was an arrangement to honor her grandmother’s wishes, a counter-narrative has emerged. A cousin of Mary's has claimed in a recent docuseries that the marriage wasn't strictly a legal requirement from the will, but that Mary and Robert Sr. had actually "seemed to fall in love" at the time.

This claim suggests the relationship was not merely a transactional inheritance but had a genuine romantic component, further complicating the public's understanding of their bond.

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Fresh Family and Church Drama: The Latest 2025 Updates

The Cosby family’s drama extends far beyond Mary and Robert Sr.’s unique relationship. Recent events in late 2025 have brought their family and church affairs back into the spotlight, confirming that the controversies are far from over.

4. Robert Cosby Jr.’s High-Profile Divorce Filing

In a very recent development, Mary and Robert Sr.'s son, Robert Cosby Jr., is navigating a public divorce. His wife, Alexiana Smokoff, officially filed for divorce in a Utah court in November 2025. This legal action comes amid ongoing family strife and adds another layer of complexity to the already dramatic Cosby family narrative.

5. Ongoing Cult and Financial Extortion Allegations

The Faith Temple Pentecostal Church continues to be a focal point of controversy. Ex-members have repeatedly accused Mary and Robert Sr. of running a cult and engaging in financial misconduct, alleging that the couple pressures congregants for money and controls their personal lives.

• Docuseries Scrutiny: A recent TLC docuseries has delved into the decades of family drama, lawsuits, and the cult allegations, keeping the scandal fresh in the public consciousness.
• Legal Troubles: Mary has faced legal issues, including a misdemeanor charge for unlawfully providing a shelter, further fueling the narrative of a controlling or problematic ministry.

The RHOSLC Connection and Net Worth

Despite the controversies, Mary Cosby has maintained a presence on *The Real Housewives of Salt Lake City*, returning for Season 4 and Season 5 as a "friend of" the Housewives, ensuring her family life and church remain a topic of discussion.

Mary Cosby’s estimated net worth is reported to be around $5 million, a figure largely attributed to the inherited assets, businesses, and church-related income she received after marrying Robert Sr. and assuming control of the family empire.

Conclusion: The Enduring Legacy of Mary and Robert Sr.

Mary Cosby and Robert C. Cosby Sr. have built a life on a foundation that is both spiritual and deeply controversial. Their marriage, born from a unique family mandate, has survived decades of scrutiny, an age gap, and the pressures of reality television.

As of late 2025, the couple remains united, with Mary calling her husband her "rock" despite the continuous barrage of accusations against their church and the very public drama of their son's divorce. Their story is a complex, almost unbelievable saga of faith, fortune, and a family legacy unlike any other in America.