In a finale featuring two segments, taped six weeks apart, Jason Mesnick is first seen proposing to Melissa Rycroft, then breaking up with her and pledging his love to runner-up Molly Malaney, who agreed to give him a second chance.
The ending has created a lot of buzz on the Internet, with some people speculating the finale was rigged to create more excitement.
"That's patently untrue. It was (Jason's) choice in New Zealand who he proposed to," Fleiss told People magazine, adding that after the show ended, "He was not in love with Melissa anymore and he was in love with Molly and he needed to make a change."
"The Bachelor" host Chris Harrison also told the magazine: "We haven't shown breakups before, but we've never had this situation. We couldn't not show that."
Fleiss emphasized no one saw Mesnick's change of heart coming.
"(I) was in the process of trying to talk Molly into being 'The Bachelorette' (on a companion dating series)," Fleiss told People. "She was finally starting to come around and saying she wanted to do it, and she had spoken to her family ... I thought she would be a fantastic 'Bachelorette,' so likable and beautiful and telegenic."