By Gina Serpe Tue Sep 26, Looks like Aaron's next party won't be of the bachelor variety. Aaron Carter and his fiancee, model/aspiring actress Kari Ann Peniche, brought new meaning to the term fickle hearts over the weekend, confirming they had broken off their engagement, after a less than whopping six days. "It was a big blur," the 18-year-old singer said on Ryan Seacrest's Los Angeles radio show Monday. "It wasn't a big deal. I made a mistake, and she made a mistake, too." What a difference a week makes. Carter said he popped the question, after knowing Peniche for just five days, and that he "acted on impulse...Is that a good excuse?" "Don't get me wrong, I do want to be a married man one day, but just with the right person...I want a good girl, and it's really hard to find one." Carter also told Seacrest the proposal was not planned. "All of a sudden, somebody threw it out there as a joke, and I said, 'Alright, I'll do it.' " Carter popped the question to the 22-year-old former Playmate in front of 200 people Sept. 16, proposing onstage in Las Vegas during a performance of the Playboy's Hollywood Comedy Tour . Peniche, who also happens to have been involved Carter's brother, Nick, said after the betrothal that she was "very excited" about the impending vow swap, and they hoped to tie the knot within six months. On the bright side, at least wedding guests won't have to sit through a particularly awkward best man speech. "I don't like her," said Nick. The Backstreeter denied to Seacrest he "dated" Peniche but admitted he'd "hooked up with her." "I feel bad for my brother," the elder Carter said. "He was looking for love." For her part, Peniche confirmed the change of heart, though while Carter claims he called off the engagement, his ex-fiancee phoned in Monday to the Playboy Morning Show on Sirius Satellite Radio and said it was more of a mutual decision. "As romantic as it was and how surprising...reality set in," Peniche said. "Aaron is one of the most genuine people I know, and he has an amazing heart, but we realized that, at our age, we weren't quite ready for the commitment of marriage. "You know, he has a lot of emotional problems, and I just want him to get healthy and happy. I just want him to become stable," she continued, saying she and Aaron Carter hadn't ruled out getting back together in the future. The engagement was officially scuttled on Friday, said Peniche. The following day, Aaron rang up family patriarch, Bob Carter, seeking advice. "He said, 'Dad, what should I do? What do you think about this?' " the elder Carter told E! Online senior editor, Marc Malkin. "I said, 'Son, I know you're 18, and you think you're an adult, but you're still a kid. Don't make any rash decisions....I told him you don't go looking for love, you don't go asking for love. It will happen when you're not looking for it.' " And in her own statement, the Carter kids' mom, Jane Carter, said, "My love for all my children does not waiver...I want him to be happy, period."