Just before her season of The Bachelorette began airing in May, Becca Kufrin let a major spoiler slip: Yes, she’d gotten engaged to one of the contestants. “It feels so good to say it — and this time, I think it’s going to stick!” said Becca, who had accepted Arie Luyendyk Jr.’s proposal on The Bachelor, only to have him dump her on camera weeks later. “Looking back, as weird as it sounds, I can really only thank [Arie],” she said. “It allowed me to go on this new journey…to find the person who is a better suit, better fit for me.”

Becca’s no longer so sure about that. Six weeks after making her happy announcement, she fears she may have picked the wrong guy, Life & Style has exclusively learned. And she’s stopped making wedding plans as she rethinks her decision. “She was so quick to announce her engagement, but it’s cooled off and she’s not thinking about a wedding,” says a source. “She was so confident when she chose him, but now she really has regrets.”

Becca never imagined she’d have a change of heart. Before she started filming, the 28-year-old publicist made it clear that she was not only ready to get married, but knew exactly what she was looking for in a future husband. Once she found her perfect guy, the source says, Becca intended to waste no time making things permanent, settling down and starting a family.

But no more. Since the show finished filming, she’s been secretly meeting with her fiancé, and the more private time she shares with him, the more she realizes they don’t have as much in common as she thought. “There’s tension when she’s with him because she’s been acting withdrawn,” the source reveals. Making matters worse, after watching the show over the past few weeks — and seeing sides to the contestants she hadn’t known about during the taping — Becca now thinks her instincts were off. “She doesn’t think she had enough of an open mind with the other guys," says the source. "She just spent so much of her time chasing the winner.”

She’s also been reading stories about all the men in the news and on social media, which she was deprived of during filming. As a result, she’s learned new things about them, both positive and negative. “She thought [her fiancé] was the right choice from what she knew of him during filming,” the source says. “He charmed her, she fell in love and she thought she could imagine forever with him.” The most appealing thing about the winner: He seemed very different from Arie. "He made it clear he wanted to marry her and he didn't seem like the kind of guy who would break her heart after the show ends,” the source notes.

But now she’s afraid she may have been too focused on his eagerness to get married — and not focused enough on whether he was the right match for her. “She’s learning things about him that she never knew before,” says the source. “It was all such a whirlwind when she fell in love with him. And she can’t help but think she made a rash decision.”

Weirdly enough, as she wonders if she picked the wrong person, Becca finds herself actually understanding what Arie went through. “She thought it would be easy to pick the man she wants to spend her life with, and that she’d never have the urge to do what Arie did to her,” the source says. “But it turns out picking one guy after just six weeks is a lot harder than she thought.”

For more exclusive celebrity news, be sure to pick up the latest issue of Life & Style on newsstands now.