After Sheila's birth, Theresa began drinking heavily. She regularly drank at the local American Legion Hall where she met Estelle Lee Thornsberry, a disabled United States Army veteran. The two began a relationship and eventually moved in together. During the relationship, Theresa would routinely leave her children with Thornsberry while she went out drinking. Thornsberry began to question Theresa when she stayed out for days at a time and ended the relationship a few months later after he discovered that she was having an affair with his best friend. Shortly after the relationship with Thornsberry ended, Theresa met and began a relationship with a United States Marine private named Robert Knorr. She soon became pregnant and the couple married on July 9, 1966.