Michelle Elman's romance with her husband-to-be ended just shortly after she introduced him to the public.

The relationship expert and life guru shared the heartbreaking incident on "This Morning." She recounted how she learned that her partner had been cheating on her. Elman and her now-ex, whom she introduced as Ben, were together for three years and lived together for two.

He proposed on April 13 and the following day, she introduced him to her followers by announcing their engagement on Instagram. However, hours later, she learned that he had been unfaithful.

"And yeah, in my eyes, the love of my life, the healthiest relationship I've ever had, and then we got engaged on the Saturday, and then on the Sunday, I got a DM from a woman who followed me, who'd read all my books," Elman recalled.

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"She had read my dating book about him. It wasn't about him. It was a dating book about how to be single and the last chapter was about him and had taken so much advice around it and then just said, 'Hey is your fiancé this person?' with his name and that's how it started."

Ben was with her when she received the first message from the woman who told her about his infidelity. The woman also sent screenshots of his dating profile, his number and more. Ben admitted he had been seeing the woman and others.

"My first reaction was shock and I kept saying, 'Please tell me first.' I don't want to find out from her," Elman continued, per the Daily Mail. "Then it was screenshots of the dating profile and his number, I believed her from the get go, but I needed evidence. She told me the hotel, and I said put that in your email, and it came up, then he admitted it."

Elman added, "He admitted it and to others as well, but I think my reaction was just was, 'You have ruined a good thing.' This is supposed to be [the] happiest day of my life."

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Michelle Elman
Michelle Elman attends the UK Multimedia Screening of Marvel Studios' "Guardians of the Galaxy Vol. 3" on May 02, 2023 in London, England.
(Photo : Jeff Spicer/Getty Images for Disney)

When asked if she had some inkling that something wasn't right about their romance, given that they had been together for years, the relationship expert acknowledged that it was the first question one would often ask -- if there were red flags.

"I fully back myself. I'm an emotionally intelligent, smart, switched-on woman," she said. "And I have every tool in my toolkit to notice red flags. But if someone wants to lie to you and wants to deceive you, it doesn't matter if you spend all 24 hours together. We lived together, we worked together three days out the week. If they want to lie to you, they will."

She continued, "And even looking back, like, wholeheartedly, there were no red flags. I was in a relationship with the love of my life, and the only thing that, in hindsight, I could have done was go on his phone to find out. But in my mind, as a life coach, the moment you've gone on their phone, that's the relationship over, you've already lost."

Elman and her ex met on a dating app. Before the Instagram post, which she already deleted, Elman had never revealed the face, tagged or named Ben.

"Thank you for having me on to tell my story in the kindest compassionate way. If you've been cheated on, it is not YOUR shame!" she commented on the clip of her interview shared on the official Instagram account of "This Morning."