Sean Lowe's decision to keep controversial contestant Tierra LiCausi on this season of The Bachelor wasn't driven by producers or ratings or any factors other than his own naivete, he confessed during a Sean Tells All special on Tuesday, Feb. 19.

"When I watch it back, I feel like man, I was such a fool because I feel like I was duped," he told host Chris Harrison of finally seeing LiCausi's toxic personality on the season. "My take is that Tierra should not have come on this show."

PHOTOS: Meet Sean's Bachelor women

Lowe, 29, has currently narrowed his original group of 26 women down to his final three -- Lindsay, AshLee and Catherine. But in the process, the Dallas native upset many of the ladies by keeping LiCausi on the show despite her frequent meltdowns and outbursts.

At one point early on in the season, the Las Vegas native took a tumble down the stairs at the Bachelor mansion that warranted a call to the paramedics. A few weeks later, she nearly got hypothermia during a freezing dip in the glaciers of Canada -- causing the other women to roll their eyes and Lowe to rush to her side.

The much talked-about bachelorette even verbally attacked fellow contestant AshLee at one point, accusing her of trying to "sabotage" her relationship with the bachelor. 

Lowe, for his part, was told numerous times about her terrible behavior, but opted to ignore the warnings. Now, he says, he regrets not listening to the women earlier.

"In hindsight, I wish I would have kept Jackie on the two-on-one," he mused to Harrison. "[Tierra's] a woman that simply can't get along with her peers. [And] now that I watch it back, she's getting into arguments and fights with some of the best, sweetest people in the house."

PHOTOS: The Bachelor: Where are they now?

"Being the Bachelor is not easy, it's really hard sometimes," he continued in defense of his actions and complete ignorance. "You walk away from your life for months, and I reached a point where I was like, is this all for naught? I felt like every girl was focusing on Tierra and not on me and I thought … am I wasting my time?"

LiCausi has since moved on. The 24-year-old leasing consultant is currently engaged to an ex-boyfriend, her brother Tyler confirmed to Us Weekly earlier this month. 

PHOTOS: Ugliest Bachelor splits

"Tierra got engaged in January. We're ecstatic for her. She is so happy!" he told Us. "They had been together for three years on-and-off … It made her upset that people thought she would fake an engagement to Sean. Meanwhile, she was so happy with someone else and couldn't tell anyone. It was very hard for us to keep it hush hush."

This article originally appeared on The Bachelor: Sean Lowe Tells All: Tierra "Duped" Me, Should Not Have Done Show