On September 29, 1962, 16-year-old Theresa married Clifford Clyde Sanders, a man five years her senior whom she had met a few months prior. Immediately she dropped out of high school and became pregnant, and on July 16, 1963, she gave birth to her first child, Howard Clyde Sanders. The Sanders' marriage was rocky as Theresa was possessive and repeatedly accused Sanders of infidelity. The couple argued frequently and on June 22, 1964, Theresa claimed that Sanders had punched her in the face during one such argument. Theresa reported the incident to police but refused to press charges against Sanders. The assault charges were subsequently dropped.