Since joining “The Real Housewives of Salt Lake City,” Mary Cosby’s marriage to Robert Cosby Sr. has been one of the most talked-about aspects of her time on reality TV.
Their Marriage Was Arranged by Her Grandmother
Mary has openly said her marriage to Robert Cosby Sr. was influenced by her late grandmother’s wishes.
Before marrying Mary, Robert Sr. had been married to her grandmother, Dr. Rosemary Redmon Cosby.
Mary has clarified that they are not biologically related, but the relationship still surprised viewers and became one of RHOSLC’s most talked-about storylines.
She explained on “RHOSLC” that it her grandmother’s idea for her to marry her step-grandfather.
“Before she passed, she made it very clear that she wanted me to be the one to take her place in the church and inherit everything,” Mary explained. “That came with homes, money, our church and also marrying her husband.”
She added that her inheritance was dependent on her tying the knot to Robert.
Mary continued, “Basically, Robert Sr. was 20 years younger than my grandmother. My grandmother felt like she robbed his youth. So she said, ‘If something ever happens, I want you to marry one of my girls, because I know that they will be loyal to you and treat you good like you treated me.'”
Mary and Robert tied the knot on Sept. 28, 1998, in Chicago, roughly a year after her grandmother died.
The wedding marked Mary’s transition into church leadership as well as the beginning of their decades-long marriage.
Mary Calls Robert Sr. Her ‘Rock’
In an interview with PEOPLE in October 2025, she explained how even after decade together the two “still love each other.”
“I see us just getting old together, and I’ll be always standing there,” she added. “He’s just this solid piece in my life and my son’s life, and we couldn’t do it without him. We could not live life without him.”
Together the couple are leaders at Faith Temple Pentecostal Church in Salt Lake City, founded by Mary’s grandmother. Robert Sr. serves as bishop while Mary holds the title of first lady, continuing the church’s family legacy.
They Share One Son Together
Mary and Robert welcomed Robert Cosby Jr. years after their wedding.
He appeared occasionally on “RHOSLC” and spoke about struggles with addiction and mental health before his death in February 2026 following a reported medical emergency.
The two released a statement after his tragic passing.
“Though our hearts ache, we take comfort in God’s promise and in knowing he is finally at peace,” Mary and Robert Sr. said. “We are grateful for your prayers and trust in the Lord to carry us through this time of sorrow.”
