Colton gave Cassie his final rose on The Bachelor's 23rd season, which filmed in late 2018 and aired in early 2019. The pair dated for about 18 months and discussed getting engaged before announcing their breakup in May 2020.
According to an insider, Coming Out Colton's production team approached Cassie to appear on the series, which just premiered Friday on Netflix, only a day after Colton first came out as gay, publicly, on Good Morning America in April 2021, Varietyreported.
Two different sources informed the website that Cassie -- who allegedly had no idea Colton was gay until he shared the news with the world -- had declined to participate in Coming Out Colton despite being offered payment for her participation.
Producers reportedly hoped Colton and Cassie would sit down for a candid chat about Colton being openly gay as well as the mistakes Colton had made once the couple decided to end their relationship.
What started out as an amicable split last year turned nasty when Cassie accused Colton of trying to "monetize" their breakup by writing about it in his The First Time memoir as well as stalking and harassing her, which resulted in Cassie filing a restraining order against the former NFL player in September 2020 followed by a police report several weeks later.
Colton allegedly put a tracking device on Cassie's car, sent her "unsettling" text messages, and would stand outside her apartment or her parents' house very late at night.
Colton later told multiple press outlets Cassie ultimately dropped the restraining order after they were able to reach an agreement in private that addressed Cassie's concerns.
Cassie, Colton and Netflix all declined comment on Cassie's alleged refusal to be involved with Coming Out Colton when contacted by Variety, but a person familiar with the situation said Cassie is not interested in rehashing her painful past or being associated with Colton going forward.
Colton admitted he truly "fell in love" with Cassie, which led him "to spiral" after the breakup because he "thought I'd found someone who could make me straight," according to People.
"And I didn't want to let it go... I really lost myself," he noted.
FOLLOW REALITY TV WORLD ON THE ALL-NEW GOOGLE NEWS!
Reality TV World is now available on the all-new Google News app and website. Click here to visit our Google News page, and then click FOLLOW to add us as a news source!
Colton told Variety in May that he and Cassie had agreed not to discuss the details of their relationship in the press, but he insisted, he "did not physically touch or physically abuse Cassie in any way, shape or form."
Colton's intentions and sincerity have been questioned for filming a docu-reality series about his sexuality in the aftermath of his messy split from Cassie, and a Change.org petition even gathered more than 35,000 signatures demanding to cancel the show.
But Colton said he doesn't want anyone to think he's "coming out to change the narrative" or to "brush over" how he had treated Cassie.
"[I want to] take responsibility for my actions... Controlling situations to try to grasp at any part of the straight fantasy that I was trying to live out was so wrong," Colton admitted.
Colton also said in May, "If there was anything I could do to take more ownership, I would. But also, out of respect to [Cassie], I don't want to get into the details."
"I want this interview to be the last time I address her," he added, "because it's not fair for her to have her name in articles every time I talk. I'm sorry, and I want her to know that I hope she has the best, most beautiful life."
And Colton reportedly says on Coming Out Colton, "There's only so much that I can do in regards to the Cassie of it all. Legally, I can't talk about it and the only person I have to blame is myself."
A trailer for Coming Out Colton that was released on Monday showed Colton confessing he had put Cassie "through hell" during his coming-out journey.
Colton's dad Scott Underwood was shown telling the former pro football player that he "went off the rails," and a friend appeared to scold Colton for how he had behaved with Cassie, saying, "What you put her through was bullsh-t."
Colton previously said in the press that he went through a very dark time following his split with Cassie and even attempted suicide one evening.
But Colton is now reportedly dating political strategist Jordan C. Brown, and Cassie moved on with musician Brighton Reinhardt, with whom she reportedly couldn't be happier.
Colton told GMA earlier this year that he realized he was different at the age of six and came to the conclusion he's gay when he was a freshman in high school.
Colton said he hated himself "for a long time" and was "a miserable person living as a shell of a human being" while pretending to be straight for well over a decade.
"I'm not asking for a fresh start," Colton told People. "But now that I am my authentic self and now that I can live life on my own terms without a secret, I can promise that I will do my best to become a better person."
Meanwhile, Cassie is reportedly eager for a fresh start, as a source told The New York Post's Page Six earlier this week that she "really just wants to move past any drama having to do with Colton."
"She's being roped back into all this Colton mess because of the Netflix show," the source said, adding that Cassie has "a lot of bad memories associated with the end" of her Colton relationship.
"She wishes there was a way to completely separate herself from his narrative."
The source acknowledged, however, that Cassie fully supports the LGBTQIA+ community and is glad to hear Colton is genuinely sorry and holding himself accountable for his actions.
After coming out as gay on GMA, Colton revealed to Variety he had experimented sexually with men prior to appearing on Becca's season of The Bachelorette in 2018, which preceded his Bachelor in Paradise and The Bachelor stints.
Colton disclosed that he had a few sexual encounters with men when he was in his twenties but never had sex with a man or woman prior to his time on The Bachelor franchise.
"When I say 'hookups,' not sex," confirmed Colton, who had met these men under a false name in 2016 or 2017 through Grindr, a gay dating app. "I want to make that very clear that I did not have sex with a man, prior to that."
In special GMA footage that aired April 15 on ABC's Nightline, Colton lamented of Cassie, "I don't know if I ever will get the chance to sit down and talk with her. I would like to. I would like to say sorry for how things ended. I messed up. I made a lot of bad choices."
He continued, "I made mistakes at the end of that relationship and I ruined the good memories we had by my actions and what I did to hold on to being straight because I didn't want to look myself in the mirror. So for that, I'm extremely, extremely sorry."
Colton added at the time how he's sorry from the bottom of his heart.
"I'm sorry for the pain and emotional stress I caused. I wish it wouldn't have happened the way it did," Colton acknowledged, adding that he regrets how he had misled his The Bachelor bachelorettes.
"I wish I would have been courageous enough to fix myself before I broke anybody else... Do I regret handling [The Bachelor] the way that I did? I do. I do think I could've handled it better... I just wish I didn't drag people into my own mess of figuring out who I was."