Robert Cosby Jr.'s ex-wife, Alexiana Arian Smokoff, is mourning his unexpected death. "Alexiana knows he passed away. She is pretty shaken up," a source exclusively tells Us Weekly. "Everyone is upset. Everyone loved Robert." Us confirmed on Wednesday, February 25, that Robert Jr. - the son of Real Housewives of Salt Lake City star Mary Cosby and her husband, Robert Cosby Sr. - died at age 23. An official cause of death has not yet been revealed. Alexiana filed for divorce from Robert Jr. in November 2025 weeks after he was arrested for violating a protective order.