Jackie + Hyde

The whole relationship starts in season 3 when a depressed Jackie turns to Hyde. The two go out on a date in the episode "Jack Bags Hyde" (308). After kissing, Jackie decides she doesn't have feelings for Hyde and Hyde agrees, but the look on his face tells a different story.

In the episode "I Can't Quit You Babe" Eric and Donna catch Jackie and Hyde making out. After that the two are together for a while until it becomes apparent that Jackie still has feelings for Kelso. In the season 5 finale Kelso and Hyde force Jackie to choose between them once and for all. In the end she finally makes up her mind and chooses Hyde.