The time has come forZach Schallcrossto make his most difficult decision yet.

As hisBachelorjourney comes to an end, Zach has to decide whether he wants to move forward with Kaity or Gabi, with whom he brokehis “no sex” decree during Fantasy Suitesweek.

“It’s the biggest day of my life,” Zach, 26, says in PEOPLE’s exclusive sneak peek at Monday’sBachelorfinale. “My heart has been yanked in two directions.”

Account executive Gabi, 25, knows that the day can go one of two ways for her: “Today, I am left heartbroken or going to be engaged to someone really amazing and special to me.”

Ricky Middlesworth/ABC; Nino Muñoz/ABC; Ricky Middlesworth/ABC

THE BACHELOR - ABC’s “The Bachelor” stars Kaity. (ABC/Ricky Middlesworth); THE BACHELOR - ABC’s “The Bachelor” stars Zach Shallcross. (ABC/Nino Muñoz); THE BACHELOR - ABC’s “The Bachelor” stars Gabi. (ABC/Ricky Middlesworth)

Meanwhile, ER nurse Kaity, 27, worries whether or not Zach will choose her in the end.

“If he got down on one knee and proposed to me, it would change my life forever,” she says. “But it’s very scary the thought that he’s falling in love with Gabi, too.”

After Zach and Gabi’s overnight date, the sales account executive confessed his feelings for her.

“I’m falling in love with you,” he told Gabi. “You’re someone what would be awesome to go through life with.”

In the clip from the upcoming finale, Zach acknowledges he’s “caused pain” throughout the season. “I’ve made mistakes,” he says. “And I have to share with someone very special to me that it can’t be us.”

Zach already made the difficult choice of bidding farewell to Ariel after Fantasy Suites.

Ricky Middlesworth/ABC

Zach Shallcross’ Official Bachelor Cast

“This week, I, at times, felt like a failure,” Zach told his three finalists ahead of the rose ceremony. “I’ve caused pain, I’ve made mistakes and I’m so sorry for that.”

He made that call in hopes of trying of making the week go smoothly. “This is the only thing that feels right and comfortable for me,” Zach told hostJesse Palmer. “And [sex] can really muddy the situation.”

Ultimately, Zach thought that being intimate with three different women was “not how I imagine a healthy engagement should start.”

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The Bachelorseason 27 finale airs Monday at 8 p.m. ET on ABC.

source: people.com