While Carly has openly discussed the couple's divorce on social media and Evan said in June he's "dating" again, it appears there is a chance the couple could get back together.
"Don't close the chapter on this love story yet," Zak, who competed on Season 9 of The Bachelorette starring Desiree Hartsock, toldUs Weekly on Tuesday.
"There are pages still to be written," he added.
Zak spoke to the magazine just one day after Carly was rushed to the hospital on Monday night and Evan apparently stayed by her side. Evan revealed on Instagram that Carly was discharged nine hours later on Tuesday morning "in pretty rough shape" and she "may have to go back" to the hospital.
Zak's opinion or insight into Carly and Evan's marriage is similar to what The Bachelor alum and Carly's good friend Jade Roper had expressed in May.
As for whether Jade is rooting for Carly and Evan to get back together, she said, "I just want [Carly] to be happy."
"So if that's what makes her happy, you know, then I'm going to support it. But I just want to see her happy and thriving," noted Jade, who has three kids with her husband and former Bachelor in Paradise 2 co-star Tanner Tolbert.
Carly and Evan share a two-year-old son Charles "Charlie" Wolf, whom they welcomed in November 2019, and a three-year-old daughter Isabella "Bella" Evelyn, who was born in February 2018.
Carly's representative told E! News in May that the former cruise ship singer and Evan "wish to have a civil relationship with each other for the best interest of their children."
"Carly and Evan shared Mother's Day together to catch each other up on their lives, and discussed co-parenting and the children's summer schedules," Carly's rep said.
Carly admitted in late December she was "very sad" after her breakup with Evan and going through a divorce "just sucks."
Although Carly wrote on Instagram "all wounds heal" at the time, she opened up to fans via Instagram Stories about the pain she was experiencing.
"I've obviously never been through a divorce before, so I don't really understand how this process works. I'm kind of learning as I go. Every new little thing just sucks," Carly admitted after thanking her followers for their support and kind words. "It's hard... COVID sucks and 2020 just sucks."
Evan didn't break his silence about the split until April, when he suddenly made a social-media comeback, Us reported.
"Obviously, as someone who has just been quiet through this whole process and, like, I feel like I'm an easy target because in the absence of information from one side, you just sort of fill in the gaps or whatever, believe whatever, which is fine," Evan reportedly said at the time.
"But I just want you guys to have some empathy."
Evan also insisted he'll never look for love on The Bachelor franchise again.
"I've literally done everything on the Bachelor," Evan quipped on Instagram last weekend.
"Been a complete spazz, looked like an idiot, engagement, marriage, a damn ultrasound, sex reveal, my kids are freaking babysat there -- what the hell else could I do?! Chase after an [Instagram] influencer?!... WHAT MORE COULD YOU POSSIBLY WANT."
Carly and Evan fell in love in Puerto Vallarta, Mexico on Season 3 of Bachelor in Paradise and got engaged during the September 2016 finale.
Evan -- who also has three older sons from a previous relationship: Nathan, Liam and Ensley -- pursued Carly with determination only to face resistance in the beginning of the season, but Carly slowly fell in love with his quirks and personality.
The former Nashville-based couple went on to tie the knot in June 2017, and their wedding ceremony aired during an episode of Bachelor in Paradise's fourth season on ABC.