'The Bachelor' 's Arie Luyendyk Jr. Explains That Heartbreaking Twist: 'I Made a Huge Mistake'

Warning: This post contains Bachelor spoilers.

Arie Luyendyk Jr. shocked Bachelor Nation on Monday night’s finale when he proposed to Becca Kufrin … only to break things off in the hopes of a second chance with runner-up Lauren Burnham.

And the professional auto racer understands why fans were outraged after watching the unedited footage of his incredibly raw breakup with Kufrin, 27.

“There’s been a lot of guilt and a lot of shame,” Luyendyk Jr., 36, tells PEOPLE exclusively in this week’s issue, on stands Friday. “I know it must have been extremely difficult for Becca. But I only had one foot in that relationship, and that wasn’t fair to her.”

So why did he pop the question in Peru if he felt so conflicted about his final choice?

“I didn’t want to let anyone down. But I needed more time to make that decision. I made a huge mistake,” he says. “I went with my head, and I shut down those feelings for Lauren. The relationship with Becca was great, but my heart wasn’t with her.”

Confused about his emotions, Luyendyk Jr. sought the advice of people who’d been in his position before.

“Immediately after the proposal, I just had this hole in my heart. I tried to concentrate on my relationship with Becca, and I really made a push to make it work.But I wasn’t getting over Lauren,” he says. “I leaned on former Bachelors and Bachelorettes, like Rachel [Lindsay], JoJo [Fletcher], Sean [Lowe], and asked them, ‘Is this normal?’ Everyone was like, ‘Yes, give it some time.’ I was very open with Becca about how I was feeling. It must not have been easy for her. But I knew that it was more than just missing someone. I had to take this risk.”

Did that risk pay off? Find out on After the Final Rose, airing Tuesday at 8 p.m. ET on ABC.