His ex-girlfriend, Haley Stevens, told ET last month that they were in a serious relationship and that he planned to return home to her after filming. When Brown confronted Wyatt on Tuesday's episode, he first tried to say he was just "hanging out" with Stevens (despite their trip together and multiple "I love yous"), but later admitted that he didn't properly end things with her before dating Brown.
During that dramatic confrontation, Brown brought up Wyatt partying with girls in Nashville -- so does she think he cheated on her?
"I don't think he cheated on me, no," she told ET's Lauren Zima in New York City on Wednesday. "I think he made some poor decisions of when you're in a serious [relationship], you're engaged, and it's something so public, you have to really be careful of who you allow in your life and protecting that relationship, and I don't think he always protected that relationship."
"I do think that he lied, and I think that there was not the foundation of trust and honesty that I have also preached that I wanted," Brown said. "I think that he has qualities and will learn a lot from this."
The Alabama native said her breaking point with Wyatt was when Stevens came forward to tell her story -- which didn't match up with what he had told her.
"It was really hard to see myself with my head up high after this, and I wanted to be able to really take all that I've learned from being a part of The Bachelor and The Bachelorette and be the strong woman who knows what she's worth, doesn't settle," she explained. "To be able to do that, I needed to be on my own, and that wasn't a relationship that I ever wanted to be a part of. That's not what I thought I was in."
Brown said she can't speak to whether Wyatt actually wanted to marry her, but shared that she believes he did love her.
"I think he probably wasn't ready for an engagement," she expressed. "But I do think that he was falling in love with me, and just made selfish choices, and didn't realize really what this snowball effect would be."
The interior designer said she could see Wyatt "trying to justify" how he behaved during their final confrontation.
"I don't know if he was lying... I think that's truly what he believes their relationship was -- not exclusive, what he did, I think he thought... I think he really hadn't put together what that would feel like for her... how it would affect our future. I think he realizes that now," she offered.
As for her message for Stevens, Brown hopes she gets a happy ending. "I've been in a similar situation in the past before, and from this, I hope she's learned a lot just like I have and she knows her worth and what she deserves," she said. "I hope that she can find someone that truly makes her happy one day too."
"I think it's hard [to watch the proposal back], because the whole thing is tainted, and yeah, the proposal is cringeworthy more so because you're watching a girl think she's getting everything she wanted, and I didn't," Brown shared.
"I definitely think that this has been a huge learning experience for him, and I know that he's sorry, and the guy that I fell in love with is in there," she added. "And I think this has really made him reflect on his life and his choices and I do believe that he will be a good man for somebody someday."