Edna is divorced and frequently flirts with any man she can find. She smokes, even during class, and has long since lost her passion for teaching. According to Sideshow Bob You only get one chance with Edna Krabappel.
Edna and Seymour have been shown occasionally flirting over the course of the series. When the two had a moment alone at Martin's birthday party, they finally gave in to their temptations and started making out, not realising Bart was watching. After Bart outs the two to the entire school, Seymour and Edna pretend to break up as a way of hiding their affair.
Edna became increasingly irritated by Seymour's dependence on his mother. After agreeing to marry him, she found out Skinner wasn't committed enough. She then broke off the engagement.
Edna took a liking to Ned Flanders after he saved her life. When she realised he wasn't like the other men she'd dated, she agreed to settle down with him. Edna has a positive influence on Ned, encouraging him to stand up to Homer. After finding out about her history with other men, Ned begins to have his doubts, but is willing to give the relationship another try. The two are now currently married. However, Al Jean announced Edna would be retired in due to the death of Marcia Wallace (her voice actress) on October 25, 2013. The process began in "Four Regrettings and a Funeral" when "We'll really miss you Mrs. K." was shown on the chalkboard during the title sequence, which premiered nine days after Marcia's death. In the Season 25 episode "The Man Who Grew Too Much", Ned and Nelson both said that they miss her. Her death was indicated by Ned wearing a black armband.
Despite their antagonism for each other, there are many instances where Bart has displayed signs of having a crush on Edna. After finally passing a test, Bart was so happy he kissed her, not realising what he'd done until he'd finished running over town and cheering. Another time, Bart dreamed that Edna passed him out of the goodness of her heart and he playfully slapped her on the butt. Bart also tried pulling a prank on Edna by pretending to be her ideal boyfriend. After agreeing to a date, he saw how heartbroken she was that her fake-date never came and decided to make it up to her. When Skinner pushed Edna too far, Bart offered to go on a pity-date with her as a way of taking her mind off him
Over time, Bart and Edna have since abandoned their personal gruges against each other and have become friendly enemies, only getting in each other's way over school-related affairs.