Not holding back. Shawn Booth spoke publicly for the first time about his ex-fianceé, Kaitlyn Bristowe, moving on with fellow Bachelorette alum Jason Tartick.

“[I’m] trying to understand things right now. I guess this goes with her new relationship too. It just kind of makes me question everything that we’ve had,” Booth, 31, said in Us Weekly’s exclusive sneak peek of Ben Higgins and Ashley Iaconetti’s “Almost Famous: In Depth” podcast, which airs on Sunday, January 27. “So I think that’s one of the major questions that runs through my mind — just trying to understand that, which I think is tough to understand.”

Booth and Bristowe, 33, who got engaged during season 11 of The Bachelorette in 2015, split last year after three years together. The pair announced that they called off their engagement in a joint statement in November 2018. Bristowe and Tartick, who competed for Becca Kufrin’s heart on season 14 of The Bachelorette, went public with their romance earlier this month. The former ABC star even admitted on January 16 that she considers Tartick, 29, her boyfriend.

The personal trainer told Higgins and Iaconetti that while Bristowe’s new relationship upsets him, he is trying to look on the bright side.

“I do care about her, so I am happy that she doesn’t have to, I guess, deal with, maybe, all the pain and the heartbreak because it seems like she’s moved on and she’s happy. It does make me a little more comfortable knowing that she’s not at home at our empty house, so I look at it from that point of view,” Booth said in the sneak peek. “I also think that it’s helping me to move on because it does hurt that much, but seeing everything, it does upset me and does make me a little angry, but it also helps me to move on knowing that maybe we weren’t right for each other and that I will find somebody down the road that also makes me happy.”

Booth also admitted that he and Bristowe “had a rough go right out of the gates.”

“It was a pretty dramatic season,” Booth told Higgins and Iaconetti. “I’m not going to lie and sugarcoat it and say it was all roses right out of the gates. I think we had a tough time with our relationship in, like, the second week of the season. We went through all different types of ups and downs.”

“And then obviously once we’re engaged and we’re able to announce that we’re together, we’re happy, we’re excited and then you still have to deal with other issues,” he continued. “I had a tough time on that show. It was always a battle of my heart vs. my brain. I think the whole Nick situation was a big part of our relationship.”

During Bristowe’s season of The Bachelorette, season 10 contestant Nick Viall joined the show to pursue a relationship with her after they spoke online. Bristowe and Viall then shocked fans when they had sex before the fantasy suite dates.

When asked by Iaconetti if he “ever got over the Nick situation,” Booth admitted it was “always in the back of my mind.”

The “Ben and Ashley I Almost Famous Podcast” airs weekly on iHeartRadio.