In addition, when Teddy says in her video diary that Beau is single after breaking up with his girlfriend, she notes that she smiled at him being single. He does become Teddy Duncan's boyfriend in between the episodes Teddy's New Beau and Teddy's Choice.
As stated above, Beau Landry is first introduced in the Season 4 episode Rat-A-Teddy. In the episode, Vern quits Bob's Bugs Be Gone and starts his own extermination business. Beau applies for the job of being Bob's new assistant. Beau's first extermination project is to catch a rat in PJ and Emmett's apartment where Teddy and her friends are having a sleepover.
In the end, Bob hires Beau, who starts to see something in his daughter, Teddy. In Charlie 4, Toby 1, Teddy helps Beau call his ex-girlfriend from his hometown who still has feelings for him. In Teddy's New Beau, Beau takes Teddy to a local country western hangout with another girl so that it's not considered a date, but the other girl doesn't show up. Instead, Beau and Teddy enjoy the night by themselves.
At the end of the episode, it is revealed that Beau had never really invited another girl to join them, and that he only told Teddy this so that she would agree to go with him to the hangout (he knew about her being reluctant to date). He also tells Teddy that he wants to go out with her, and kisses her on the cheek.
In Teddy's Choice, Teddy invites Beau to her 18th birthday, but her ex-boyfriend Spencer shows up and she must choose between Spencer and Beau. In the end, she chooses Beau over Spencer even though Spencer wanted them back together. In The Bug Prom, Teddy goes to the Bug Prom with Beau and his aunt, Karen, who happens to be Amy's ex-boss
In Bob's Beau Be Gone, Beau moves back to Tennesse for good, leaving Teddy sad and Bob devestated, but eventually they both get over it; Teddy helping Bob to videochat.