When Sister Wives star Meri Brown admitted to having an affair with a stranger she met online, she had to accept the fact that she was unfaithful to her spiritual husband, Kody.

Little did she know that while she was being disloyal to her partner, she was also betrayed by one of her own “sister wives!”

RELATED: ‘Sister Wives’ Cheating Scandal Grows — More Voicemails From Affair Exposed

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Meri (far right) with her “sister wives” (L to R) Christine, Janelle and Robyn and their husband Kody.

Shortly after the 44-year-old admitted she entered an online relationship with someone who lied about who they are, an insider told In Touch magazine, on newsstands now, that Kody’s youngest wife, Robyn, knew Meri was being “Catfished” the whole time, yet betrayed her “sister wife” by not doing anything to stop it!

RELATED: Kody Brown To Be a Father — For the 18th Time!

“Robyn absolutely knew from the beginning that Meri was being catfished,” a source close to the pregnant 36-year-old explained to In Touch. “Robyn sat back and just watched as the whole scam unraveled.”

Even one of Robyn’s closest friends, Kendra Pollard-Parra, admits to knowing about Meri’s relationship earlier on — revealing she told Robyn about it after fans of the show reached out to her with information about Meri’s affair.

“I brought it up to Robyn and we looked and we saw there was definitely a relationship going on,” she tells In Touch.

It’s a shock because Meri and Robyn have always been close. Meri even legally divorced Kody so he could marry Robyn, a selfless move to make sure that Robyn’s children from another marriage had access to Kody’s insurance and benefits.

LISTEN: Voicemails Left By ‘Sister Wives’ Star Meri Brown Reveal Details Of Her Miserable "Marriage"

Meri was also the one who introduced Kody to his fourth wife and facilitated the introduction of Robyn and her three older kids to their unconventional family — but now, the mother-of-one’s actions are tearing the family apart.

Following Meri’s divorce and Robyn and Kody’s subsequent marriage, an insider previously told In Touch the reality star sought companionship online because she was “lonely,” despite being surrounded by her large family.

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By her own admission, she was unhappy. Meri told In Touch she began her relationship with her online suitor “during an emotional and vulnerable time earlier this year.”

But the latest voicemail the reality star left for “Sam,” and obtained by In Touch, reveal just how lonely she was.

“Hi! I just wanted to leave a quick little message for you. Um, just thinking about you,” she says. “Just wanted to say, you know, I’ve had a fun time getting to know you. You are a great guy… We’ve had great conversations; I’m just having fun with it! This is just really sweet… As soon as you touch down have some time, shoot me a text and let me know if you’re all safe and everything is all great, and I cant wait to talk to you again.”

Listen to the latest voicemail::

For more on the Sister Wives scandal, pick up the new issue of In Touch Weekly, on newsstands now.