Samantha "Sam" Leonard (previous surname unknown) was Hyde's Invalid-wife.
Samantha was married to a man named Larry, but after Hyde went to Vegas (after catching Jackie and Kelso in a motel room) they both got drunk and were married illegally. However, Samantha showed up at the Forman's house and told Hyde that they had gotten married. This event officially ended the relationship between Hyde and Jackie. Samantha stayed in the Forman's house with Hyde for some time. Hyde's and Samantha's constant bickering and arguing drove Kitty and Red mad. Larry resurfaced and exposed Hyde and Sam's marriage as illegal, causing Hyde and Sam to break up for good.
Hyde did not annul the marriage mainly because he did not want to be like his father and leave his wife.