Nurys Mateo Says The Challenge 40 'Changed Everything' for Her and Olivia: 'In a Great Place Now' (Exclusive)

• Nurys Mateo felt betrayed by Olivia Kaiser after The Challenge: Battle for a New Campion, but they had to work together on The Challenge 40: Battle of the Eras
• Mateo tells PEOPLE that "it was a lot easier to fall back into the friendship" with Kaiser than she expected
• The Are You the One? vet also worked with boyfriend Horacio Gutiérrez Jr., who she calls "a solid No. 1," on season 40

Nothing repairs friendships like being forced to work together.

Nurys Mateo came into The Challenge 40: Battle of the Eras at odds with Olivia Kaiser after Mateo, 29, felt betrayed by Kaiser, 32, for not saving her when she had the chance on season 39, Battle for a New Champion. It also came out that Aneesa Ferreira allegedly told Mateo’s brother that Kaiser had been badmouthing her before the season started, and Mateo found out on a video call with her family while filming Battle for a New Champion.

But on the Battle of the Eras, Mateo and Kaiser will compete on the same team as part of Era 4.

“I'm a very forgiving person,” Mateo tells PEOPLE. “So when I went in there, I told myself, I was like, ‘I most likely will forgive her, but we probably won't be friends." Then you get there and TJ's like, ‘You guys are in a team.’ ”

Mateo says that having to work together “changed everything” for her.

“I was like, ‘Well, now we actually have to ride together, because we're in the same era and it's us against them,” Mateo says of going up against the other three eras. “So in that moment, I think I was like, ‘All right, I have to be cool.’ But also, I will say I'm such a little softie, I saw her and I was like, ‘I want to hang out with them. I want to talk to them.’ So it was a lot easier to fall back into the friendship.”

The Are You the One? alum can’t say exactly how things played out on Battle of the Eras between her and Kaiser, but “it ended up that we're in a great place now,” she teases. “There's no hate on my end at all, and I'm pretty sure there's no hate on her end either. We're slowly building on things.”

Mateo knows that The Challenge tests friendships, however, she says, “I'm hoping if I have any other crazy rivalries in the future, I am glad that it's not going to be me and her.”

As she repaired her relationship with Kaiser on season 40, Mateo had a solid supporter in boyfriend Horacio Gutiérrez Jr., who also competed in Era 4.

“I don't think I could have gone through that experience without having him there with me by my side,” Mateo says. “It was the best thing having someone that I knew for a fact, no matter what, no matter whatever happened, he was always going to have my back 100%. I knew I had a solid No 1. and nothing was going to change that. So I was really grateful.”

Still, Mateo recognizes that couples often have targets on their back in The Challenge.

“Regardless of if we weren't together, I think we would've had some type of a target,” she says. “Obviously, he's a great competitor, and then 39 went so well for me that I went in there already nervous. Us being together I definitely didn't think helped.”

Despite having a successful season on Battle for a New Championship (Mateo came in second and won $60,000), the Ex on the Beach vet worried about going up against some of the biggest winners in Challenge history on season 40.

“Season 39, it was just a bunch of us that were newbies on there, and then you hear about 40, and you start hearing who's going to be on the cast, and I'm just like, OK, so I just played with all the newbies, now I'm going to play with all the OGs that I've been growing up watching?” Mateo says. “I'm like, I have big shoes to fill. I have to not only prove it to them, I felt like prove it to myself too, that I deserve to be there alongside of the greats."

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The Challenge 40: Battle of the Eras premieres Wednesday, Aug. 14, at 8 p.m. ET on MTV.