 In the last years of her life she suffered from depression and heart trouble, while her husband began to lose his eyesight, becoming almost completely blind in 1986.In 1976, then 61-year-old Sheldon wrote Silverberg expressing her desire to end her own life while she was still able-bodied and active, but saying that she was reluctant to act upon this intention, as she didn't want to leave Ting behind and couldn't bring herself to kill him.Later she suggested to her husband that they make a suicide pact when their health began to fail.