Bobby and Karen
They were married and a normal couple. 3 days before Karen got possessed by a demon and Bobby was forced to kill her, the two had a fight about having children. After this incident, it drove Bobby to become a hunter and he now knows how to exorcise a demon. Bobby admits to himself in Death's Door, he would have lied to make her happy and regrets that fight. Although, he still regrets killing his wife. In Dead Men Don't Wear Plaid, Death brings Bobby's wife back. He is happy to see her and protects her fiercely. Karen also protects Bobby, by not telling him that she remembers him killing her. In the end though, she does tell him and asks Bobby to kill her again. Bobby kills her again. Saying that she was the love of his life and the fact that he has had to kill her twice, kills him inside.
Bobby and Rufus
Bobby and Rufus have a working relationship. They never mention their relationship until ...And Then There Were None where it is pointed out that Bobby and Rufus used to work together, until Bobby messed up and got someone killed. They didn't talk for many years, until Rufus called saying he found Bela. Rufus also helps Bobby in his quest to get his soul back from Crowley. They also work together again investigating the new creature. Although, it is Bobby possessed by the Khan worm who kills Rufus. It is Rufus's death that drives Bobby to go after the Mother of All. In his coma state, Bobby turns to Rufus for help in escaping that reality and dealing with the reaper.
Bobby And Ellen
Their relationship was a friendly relationship. They worked together on closing the Devil's Gate, after Ellen showed up at Bobby's house. It is unknown how long they have known each other but they have probably been friends for a long time through the Roadhouse. When Ellen dies, Bobby grieves her death with Sam and Dean. Their relationship turned romantic when Balthazar saved the Titanic in My Heart Will Go On. In the alternative universe, he and Ellen are married. She is able to pull him out of his depression after Rufus's death. It seems they are very much in love. Bobby is shocked to hear that if they right history, Ellen dies. History does get righted, and they are no longer married. Bobby doesn't even remember being married to her.
Bobby and Jody
Bobby and Jody have a history together. Jody has been arresting Bobby for many years due to her being the town's sheriff. She didn't find out about his real job until her son become a zombie, and later saved his life. In Weekend At Bobby's, Jody helps Bobby get rid of the FBI. Bobby later asks her to get Rufus out of jail for him despite this might risk her job. At first she refuses, but does it. In Hello Cruel World, Jody calls Bobby for help when she notices her doctor is a monster. She later thanks Bobby by showing up at his cabin and cook and cleans for him. The Leviathan reveals that Bobby does have some romantic feelings for Jody, but is afraid to show it. Later on Bobby kisses her for helping him figure out how to hurt the Leviathans. Jody later tells Sam and Dean that she's sorry that he died.
Bobby and his Family
Bobby didn't have a good past with his family. It wasn't mentioned much throughout the show, until Death's Door. Bobby and his father didn't get along much. When Bobby was younger, he was afraid of his father, was constantly hit by him. Bobby's mother simply took it. Bobby's father kept telling Bobby that he broke everything he touched, and this sticks with Bobby for a while. One day when his father hits his mother, Bobby gets a rifle and shoots his father dead. His mother is shocked and tells Bobby God will punish him. This is when Bobby learns that sometimes people won't thank you for saving them. Because of what happens with his father, Bobby never has children. When Bobby revisits the memory, he yells at his father for being a jackass, and that Bobby himself managed to adopt two great kids who grew up to be heroes.
Also Check Out
Bobby and Castiel- Bobby and Castiel's relationship.