The 26-year-old DNCE frontman briefly addressed his relationship with Swift while playing "Marry, Shag, Kill" as part of "Plead the Fifth." Jonas' options were ex-girlfriends Swift, Demi Lovato and Gigi Hadid.
"We were children," the star said of his fling with Swift. "[We were] 18, 19. Young enough."
Jonas, who dated the "Bad Blood" singer for a few months in 2008, chose to marry Lovato, shag Swift and kill Hadid. He explained Lovato is "a friend" -- a "really good friend," according to his interview with E! News this week.
"She's family. We've known Demi for so many years," the star said of himself and brothers Kevin and Nick Jonas. "We've performed with her, toured with her. She's just incredible."
"It's not always the case [to stay friends]," he added. "Sometimes you have to know when to fold the cards. I don't think of her as an ex. We're really good friends. We've gone through so much together and we're really close now."