Sam and Jessica
Sam Winchester and Jessica Lee Moore went out for a year and a half before Sam left to help Dean find their father. When Sam returned the following Monday, Jessica died in a fire, pinned to the ceiling, like their mother. Little was known about their relationship, but we do know that Sam had been shopping for rings, planning to propose. He hadn’t told Jessica about his life as a hunter and never planned on it.
Sam had dreams about Jessica’s death, exactly as it had happened, before she died. Because of this, and the fact that he didn’t stay to make sure she was ok, simply dismissing them as dreams, he blames himself for her death. We see an apparition of Jessica in Bloody Mary, but it is unclear whether Sam was hallucinating or whether it was Jessica’s actual ghost. Sam had many dreams early in season one about Jessica dying, one of which was him going to her grave and as he puts down flowers a hand emerges from her grave and grabs his wrist. Presumably these nightmares were out of guilt.
|Sam and Lori|
Sam Winchester and Lori Sorenson had a small relationship in the beginning of season one in the episode Hook Man, for just one episode. Sam was reluctant to become attracted to another girl so soon after Jessica’s death. He and Lori did share a kiss though. Sam saved Lori’s life and her father’s from the Hook Man.
|Sam and Sarah
Sam Winchester and Sarah Blake had a relationship in the episode Provenance that went as far as an actual date, though the date was slightly for Sam to get information about the case he and Dean were working on. It was apparent that there was chemistry between the two. However, Sam confessed to Sarah that in his line of work (since she had found out what he did) it is dangerous for people to get close to him and he wouldn’t, couldn’t, go through what happened with Jessica again with another girl. At the end of the episode, Sarah comes close to death, but she lives and points out to Sam that maybe he isn’t ‘cursed’ as he’d thought he was. They share a last kiss before he leaves.
|Sam and Madison|
Sam Winchester and Madison had a short relationship in the episode Heart. Sam and Dean realized that Madison was a werewolf and tried to save her by killing the werewolf that bit her. When she didn’t turn the following night, they assumed it had work and she and Sam share a night together. When Sam wakes up in the middle of the night, however, he realizes that Madison has turned as she escapes out the window. The following morning she calls him and they bring her back to her apartment. She realizes that she might have killed someone the previous night and doesn’t want to do it again. She tells Sam that the only way to save her is to kill her. At the end of the episode, tearfully and completely heartbroken at the fact that he couldn’t save her, the camera focuses in on Dean in this devastating scene, as a tear slides down his face, for about ten seconds before a shot rings out in the next room.
|Dean and Cassie
Dean Winchester and Cassie Robinson had a relationship for several weeks when Dean came into her neighborhood for a job. When he had to leave, he told her what he did for a living and she thought he was making up some lame excuse to break up with her. A couple years later, she calls him, explaining that she thinks something up his alley is happening in her town. They argue a lot, and Dean tells her how much she hurt him by not believing him when it really counted, but they make up and sleep together. Dean eventually has to leave, but he says he’ll come visit.
|Dean and Jo|
Dean Winchester and Jo Harvelle met under interesting circumstances, when she held a rifle to his back after she caught him and Sam breaking into her mother’s bar. As soon as her mother realized who the boys were, though, she became very friendly and introduced herself and her daughter. Chemistry sparked between Jo and Dean, but so soon after losing his father, surprisingly, Dean wasn’t interested in flirting with Jo at all. They have a job together once, but she gets snatched by the ghost they’re hunting and her mother explains to Jo what really happened to her father; he was killed when John Winchester messed up. After this, we only see Jo once more, when Sam is possessed and uses her as bait. Dean promises to call Jo later to check up on her as he leaves. As soon as he’s out the door, Jo says simply and quietly, “No, you won’t.”