(April 21, 1984 - March 15, 1990) (divorced) (1 child)

In December 1983, Plato moved in with her boyfriend, rock guitarist Lanny Lambert. The couple married on April 24, 1984, and their only child, Tyler Edward Lambert, was born on July 2, 1984. When it was revealed that she was pregnant, she was written off Diff'rent Strokes. Her co-star Conrad Bain had revealed that she was happy about her baby, and that she would no longer be alone. Bain stated in an interview with People: "She deliberately got pregnant while doing the series, when I spoke to her about it, she was enthusiastic about having done that. ... When I get the baby, I will never be alone again."

Plato separated from Lambert in January 1988, the same week her mother died of scleroderma. In desperation over these traumatic events, she signed over power of attorney to an accountant who disappeared with the majority of her money, leaving her with no more than $150,000. She claimed the accountant was never found nor prosecuted, despite an exhaustive search, and that he had also stolen more than $11 million of other people's money. During her March 1990 divorce, Plato lost custody of her son to Lambert and was given visitation rights.