Peloton's Ben Alldis on How Having Melanoma Helped Him Support Leanne Hainsby Through Breast Cancer (Exclusive)

The 30-year-old instructor tells PEOPLE how he helped his fiancée navigate her cancer journey while quietly reliving his own

Ben Alldis is revealing that, years before his fiancée and fellow Peloton instructor Leanne Hainsby faced breast cancer, he received a melanoma diagnosis.

And the 30-year-old says that his experience allowed him to help his future wife navigate her own journey, which she shared with her fans on Instagram in January.

“When Leanne got diagnosed, I sort of relived it a little bit,” Alldis tells PEOPLE exclusively. “But it did really help me support her because I could understand the emotions that she was going through."

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Alldis, who lives in London with Hainsby, 35, adds, “Because I went through my own journey, I knew some of the places to go to speak to people. I knew that nutrition and movement are a big part of your recovery. I was able to help her with that.”

Alldis was working in the world of finance and teaching fitness on the side in 2018 when a woman approached him after taking one of his classes. “She said, ‘I’m really sorry to do this to you, but do you get your skin checked?’" he recalls.

“And I said to her, ‘Sorry?’ Normally [clients] come to you after class and say, ‘Thank you so much, that was great!' And she said, ‘I’m a GP. Please go and get your skin checked. I had a friend who I told and, unfortunately, he passed away.’”

Alldis, who has a lot of moles on his body, took the doctor’s advice seriously. “I went [to get my skin checked] the next day. They did a biopsy and, long story short, I was diagnosed with melanoma, skin cancer.”

Located on his lower back, the affected mole was a grade 3, which means the cancer cells look “very abnormal and not like normal cells,” according to Cancer Research UK.

Related: After Having 12 Melanomas Removed, Teddi Mellencamp Is Cancer-Free: 'I'm So Grateful We Caught It in Time'

“Fortunately, it was only stage 1,” Alldis says of the melanoma, which was treated with a series of surgeries. “Because they don’t know how much it spreads, they just for safety cut around the whole area,” he says, adding that he has a 10cm scar on his lower back. He also had a lymph node biopsy to make sure the cancer hadn’t spread to other parts of his body.

“I was in my early 20s, so it was a bit of a shock, but I obviously got through it all,” he says, before acknowledging that the diagnosis had a surprising impact. “It was strangely a very positive experience for me because it gave me a totally different perspective on life and changed my route.

“I was working in finance at the time alongside this job in fitness and it made me realize that wasn’t the route for me. I wanted to do something that was going to fulfill me even more and that’s when I decided to move into fitness full time. Then, funny enough, Peloton got in touch with me pretty much around that time.”

It was instructor and future Dancing with the Stars contestant Cody Rigsby who flew over to London and recruited Alldis and Hainsby (who weren’t a couple at the time). “Cody came to one of my classes. It was almost like it was destined to be,” Alldis recalls.

But unlike Hainsby, who publicly revealed her breast cancer journey in January five months after her Aug. 2022 diagnosis, he didn’t even share the information with his new employer. He says, “I didn’t tell anyone at the time because I didn’t want anyone to be worried that I wouldn’t be able to do the job. So, for about two years, I didn’t say anything.” Looking back, he says, “The way that I dealt with my cancer illness was probably not the right way.”

In January, after Hainsby revealed her news on Instagram, underneath a series of photos on his own account, Alldis wrote that he was “incredibly proud” of his fiancée who taught three to four Peloton cycling classes a week while quietly undergoing three months of chemo, which followed a round of IVF.

“I was shocked. I said to her the whole way through, ‘You don’t have to work. [Peloton] will allow you to stop and take time out,’” Alldis recalls. “She’s like, ‘No, I’m good.’ She would go to her 7 a.m. class and then we post camera classes, so classes that aren’t live, and then go straight to chemo.

“It was blowing my mind because she was slowly losing her hair across her body, but she also did a really good job of covering it up. I think she lost two-thirds of her hair.”

Although the former dancer successfully hid the side effects of chemo from Peloton fans, behind the scenes Alldis says she was “slowly but surely losing her confidence.” “We weren’t going out that much and we were just trying to focus on our health and wellness,” he says.

“Now, I think it pushed us into a good space because, even though we were healthy before, we doubled down learning about nutrition and we’ve stopped drinking. Our health and wellness habits are even better so I think for our longevity, it’s probably helped us in a good way.”

Last year was a challenging one for the couple who met at Peloton and got engaged in 2021. Hainsby discovered the lump on her breast just two days before her best friend’s funeral. “Grief is heavy. And then when you have illness on top of grief, you have anxiety and everything,” Alldis says.

Now, months after she received the all-clear, he says they are in a good place, looking forward to planning their wedding and celebrating with their family and friends.

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Alldis, whose book Raise the Bar, goes on sale in the U.S. in October, says, “Me and Leanne have very similar values. We’re both massive family people. We’re both passionate about life. We’re both very driven, but we also have this complementing energy where she’s very extra and eccentric and I’m quite stable and the finance guy.

“I think those things balance us out. So, even though our energies are different and maybe quite opposite, our values are very aligned.”

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