See Vanessa's surprising reaction.
Colt finally came clean about the true nature of his relationship with Vanessa on part two of this season's 90 Day Fiancé: Happily Ever After? tell-all that aired on Sunday. After repeatedly telling his now ex-girlfriend, Jess, that he and Vanessa were just friends all season long, he admitted that he did in fact sleep with Vanessa while they were still dating.
Viewers were also introduced to Vanessa, who made an appearance in the tell-all. Colt shared that he and Vanessa first connected online when she reached out to him and offered him support amid his tumultuous split from his ex-wife, Larissa. Both Colt and Vanessa said they instantly connected and supported one another through bad marriages, and Colt admitted that he wanted to date Vanessa immediately after he split from Larissa, but she turned him down.
"I love Vanessa," Colt declared, before telling Jess that he only dated her because Vanessa turned him down.
"And if she said yes, I would have dated her in a second," he added. "I'm sorry that you were in a s**tty relationship with me, like, it was a summer fling, at best."
He then dropped the bombshell that after he returned from Brazil to meet Jess' family -- during which he told Jess' father that he wanted to marry her -- he had sex with Vanessa.
"I don't know. Like... I have this tendency to lie to women," he said about why it took so long for him to admit the truth. "I tend to get into relationships that I shouldn't, so, like, why I lied to Jess, because I didn't want to lose her -- even though I should not have been with her at all. But, she gave me this identity. I was her boyfriend, and I wanted to be her husband, even though I don't think I even loved her."
Later, Larissa chimed in and accused Colt of already having something going on with Vanessa when he was still married to her. Colt denied the accusation, although he acknowledged that he had an "emotional affair."
"I never cheated on Larissa," he said. "At worst, I had an emotional affair with Vanessa, and I'm sorry I did that. But unfortunately, while I was married to Larissa, near the end of it, it was terrible. It was literally the worst time of my entire life. And Vanessa was the only person there who would even talk to me and just be there as a friend. And I took that, and I think I was developing feelings for her."
"Larissa, honestly, I married you," he added. "I loved you. I never wanted to cheat on you or hurt you. I'm sorry that our marriage failed. OK? What do you want me to do? I did the best I could."
For her part, Vanessa showed no remorse when it came to her relationship with Colt, explaining that Jess talked badly about her from the start.
"Like, since the first time she saw me call, she started saying, 'Oh, she's a bit**. She's this. She's that. She's sleeping with my man,'" she said. "And I wasn't at the time."
Vanessa also said that although Colt declared his love for her, for now, she wasn't interested in dating him.
"I said as a best friend, I love him to death, like, he's been there for me [at] 3 in the morning. I need to go to the hospital, he'll take me, or something like that," she said. "But like, as a boyfriend, no, I would never -- at least not right now, I wouldn't trust him. There's too much going on right now. I just feel like he doesn't know what he wants right now, so he kind of goes from girl to girl to girl seeing, like, 'Maybe this is what I'm looking for. No, not really. Maybe this one. No, not really.' So, I need him to be sure of what he wants right now."
Vanessa later ended up walking out of the tell-all after Jess called her a terrible person and cursed at her. But in a surprising turn of events, when host Shaun Robinson said they were taking a break from filming, cameras captured Colt and Jess having a heart-to-heart. Colt once again apologized to Jess for how their relationship turned out. The two broke up after she caught him sending explicit pictures to multiple women online, and after she found out he started living with Vanessa after his mom, Debbie, invited her to stay with them at their Las Vegas home.
"I'm not trying to be mean to you, Jess," Colt said. "I don't want to hate you at all. You're the one that blocked me. I'm sorry I lied to you about Vanessa, honestly. I didn't lie to your family. I really wanted to marry you. I thought I was in love with you, but unfortunately, I wasn't. I made a mistake."
While Jess said she didn't believe him, she did show some compassion towards him.
"I think now you'll learn after this situation," she said. "I wish the best for you, and for the next girl, you go be right. And slow and no lie and no cheating. And, or stay with Vanessa. Try to be nice with her, you know."
When Jess told him that he repeatedly made promises to women then discarded them once he didn't need them anymore, and that he also "played" with women, Colt said he was done with those actions.
"I'm not lying anymore, Jess," he said. "I lied to you, and I apologize, but I'm really trying to be a better person. I'm finally doing everyone right. A lot can happen in a short amount of time."
ET spoke to Robinson on Wednesday, and she talked about Colt and Vanessa's shocking revelation. Watch the video below for more.