According to Peter, the "unique" ending was "the hardest week" of his life and the final week included the preview scene viewers saw on The Bachelor's Monday night premiere in which his mother Barbara Weber was shown breaking down in tears over a girl.
"I couldn't have predicted that last week was the hardest week of my entire life. [Chris Harrison] can tell you."
Peter had added in a interview with The Hollywood Reporter "there's a reason" he believes the conclusion of his season will remain a secret and "there's no way" Reality Steve spoiler blogger Steve Carbone and others are going to find out.
Peter's disclosures have left Carbone and fans speculating Peter's love story is still playing out and the season's ending has yet to film, which is why it can't be spoiled.
While The Bachelor leads typically hand out their final rose and propose marriage during the November finale tapings, it's possible Peter may be waiting to make a move during The Bachelor: After the Final Rose's live episode in March 2020.
"[Getting engaged] at the finale, at the [After Final Rose] -- that's a good guess," Peter told ET. "You can't see this coming for a mile, so maybe. I don't know."
"She stuck out to me so much, and some people, they have their opinions, but I love the boldness. I loved her being so intentional and showing me exactly why she was there. And I think it's important to note that she's the most sweetest person," Peter told ET.
"She was doing it the right way. She wasn't being mean about it, or necessarily disrespectful to any of the women. She's the sweetest person and it worked, and I appreciated it."
And Madison Prewett enjoyed an intimate one-on-one date with Peter in which she met his family at Barbara and Peter Sr.'s vow renewal after 31 years of marriage that took place at Peter's California home.
"I lucked out with that date like no other. That could have realistically been a really awkward and uncomfortable date. That's a big thing... [and] she absolutely knocked it out of the park, killed it," Peter said.
"I was flying really high after that date. She definitely really got off to a really good lead. And you guys saw it."
Peter also seemed smitten with Kelley Flanagan, whom he had met a month prior to filming at a hotel by random chance. The pair had chemistry the moment they met, and that quickly became apparent to Kelley's competition.
"I'm thinking, 'Is this some kind of fate?' Like, why did this happen?' And I didn't know if she was actually going to show up that first night. It was a pleasant surprise," Peter shared.
"It just felt so good because I kind of already knew her," he added. "We had spent an hour talking when I first met her the first time, so it just felt very comfortable and easy and it was good chemistry. We got along well."
The Bachelor's 24th season will continue airing on Monday nights at 8PM ET/PT on ABC.
To read spoilers on how the rest of Peter's The Bachelor season unfolds, his Final 2 bachelorettes and more, click here.