'The Bachelor': Arie Luyendyk Jr. Proposes to [SPOILER], Then Dumps Her in Heartbreaking Footage

The 36-year-old race car driver made up his mind... kind of.

Arie Luyendyk Jr. made up his mind... kind of. 

The 36-year-old race car driver got down on one knee and proposed to Becca Kufrin on the season finale of The Bachelor on Monday night -- though a source previously told ET that he ended his engagement to date his runner-up. 

While both women impressed his family, they ended up siding with Becca, explaining that they thought she'd fit better with his "future," which may have been the driving reason Arie to break up with Lauren Burnham at the final rose ceremony. 

Arie said he didn't fully know who he wanted to propose to until that morning, and while Lauren felt "blindsided" by their breakup (and criticized him for getting down on one knee so soon), that didn't stop him from giving Becca his final rose and asking for her hand in marriage with a stunning Neil Lane sparkler. 

"You are beautiful and elegant and in that first conversation, I knew you were an incredible woman and I needed to know more... We're a team, and I'm very lucky that you've been on this journey with me, and through all of it, you've given me so much confidence. My love for you is unmeasurable," he said. "I choose you today, and I choose you today from here on out." 

"Becca, will you marry me?" he asked. 

"When are we having babies?" Arie excitedly asked after becoming engaged. 

"Tonight," Becca answered. 

Things got complicated after the proposal, when Arie realized that he made a mistake and pursued the wrong woman. Shocking unedited, uncut split screen footage showed the Bachelor breaking up with Becca, just weeks after their engagement. 

"The more I hung out with you, the more I was losing the possibility of reconciling things with Lauren," Arie confessed to Becca, admitting that he's been struggling since the finale. 

"Are you f**king kidding me?" Becca asks, COMPLETELY JUSTIFIED, questioning why he would bother to get down on one knee if he was so conflicted. "What the f**k?"

"You allowed me to work through those feelings," Arie explained, telling Becca that he wanted to breakup now instead of pulling a Jason Mesnick on After the Final Rose. 

"This is just a really sh**ty thing to do on your part... I want you to go," Becca said, before bursting into tears. "Just leave! What are you still doing here? Just go!" 

But Arie did not leave. Arie stuck around, seemingly only making things worse as Becca cried. "OK, I'm going to go," he finally said, before taking another four minutes to actually get up and walk out the door. 

Arie will come face to face with both Becca and Lauren on After the Final Rose, airing Tuesday at 8 p.m. ET/PT on ABC.