"Bachelor in Paradise is a special show to me, and I want its integrity to be upheld," Tolbert exclusively tells ET. "Demi is being fully hypocritical. On The Bachelorette, she called a guy out on night one for coming in with a girlfriend. I have 100 percent heard from multiple people [including other alumni,] that she [had a plan heading into Paradise]. People were talking about it back in May."
Colton Underwood has seemingly supported Tolbert's claim on social media.
On Tuesday's episode of Paradise, Burnett told Derek Peth (whom she had been dating for four days) that she was dating a woman before coming onto Paradise, and that she was exploring her sexuality. He took it well and was supportive of her journey. Viewers weren't surprised by the news -- Burnett had opened up to Hannah Brown about the relationship on the season premiere -- but promos have shown that Burnett's love interest makes an appearance in Mexico and she seemingly pursues that relationship instead of Peth.
"The Jed comparison was probably the most extreme I could have gone -- but I don't regret it," Tolbert says. "I'd compare her to Blake [Horstmann] and Hannah [Godwin], because they had an agenda. No one should go in trying to script the show. Blake and Hannah were visiting each other beforehand; let things happen on the beach."
Tolbert dated and got engaged to Jade Roper on season two of Bachelor in Paradise. They've since married and now share two children together.
"This is all good drama, and it's good TV, but these days people know they get more success and more followers from being on the shows for longer, so they have ulterior motives," he alleges.
Burnett has fought back against Tolbert's claims against her, writing that she didn't plan anything. In another tweet, she told him, "Oh f**k off, not the same at all. Maybe I can teach you a thing or two about going down on your wife @ttolbert05."
"Obviously, Demi showed how classy she can be with that. She can be funny, yes, but that was low brow, and usually when people lash out like that, it's because they're guilty," Tolbert tells ET.
As for how Peth feels about the situation, a source told ET on Wednesday that he and Burnett are in a good place, and he doesn't feel the comparisons between Burnett and Wyatt are fair.
"Derek feels like Demi has always completely told the truth to him," the source said. "He would defend Demi on any of this."
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Both host Chris Harrison and ABC exec Rob Mills have also previously told ET that they're proud of how Burnett's story plays out on Paradise this season. Harrison also said, however, that he's tried to prepare Burnett for the critics.
"I talked to her after all this was over and she was crying, we were all crying, we're hugging," he recalled during an interview with ET last week. "Everybody was very celebratory and very happy and I said, 'Just know that there's going to be negative that comes with this, from within that community and without.'... I'm prepared for that. That's just the world we live in with social media and everything else."
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Bachelor in Paradise airs Mondays and Tuesday at 8 p.m. ET/PT on ABC.