Seeking Sister Wife : Couple to Divorce in Order to Have Brazilian Woman Join Plural Marriage

A new plural family is joining TLC.

On Monday, audiences will be introduced to Garrick and Dannielle Merrifield on Seeking Sister Wife, which will document the married couple's decision to divorce and have Roberta, who is from Brazil, become a sister wife.

After living monogamously for over 10 years, Garrick — who shares sons Geremiah, 11, and Solomon, 10, with Dannielle — felt that God sent him on a road to live a plural marriage lifestyle. The couple then searched online for a few months and finally met Roberta, a Christian Brazilian (who only speaks Portuguese), who they knew they wanted to be in their family forever.

But having her come to the United States comes with a catch — the couple must split in order for Roberta to legally marry Garrick and join them in Buena Vista, Colorado.

Courtesy TLC Dannielle and Garrick Merrifield with Roberta

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"We first tried to get Roberta here on a travel visa and she was denied," Dannielle says in PEOPLE's exclusive sneak peek. "So we decided we'd meet in the middle and met up in Cabo, Mexico," adds Garrick.

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When the couple met Roberta for the first time, it "was surreal," says Dannielle. "The doubts were washed away and it was like, she's real. She's a real girl."

On the trip, the couple brought their sons and were also joined by Roberta's mother. "Everyone got along amazingly," says Dannielle. "It was just perfect."

Courtesy TLC The Merrifield family with Roberta

The trip was also where Garrick popped the question — and was intimate with Roberta for the very first time.

"It was just a magical moment," Garrick says of the proposal.

"And that was the first night Garrick and her were intimate," says Dannielle, who explains that they "had talked about rules and intimacy before that first trip and meeting Roberta and we didn't want any intercourse to happen until we knew that she was supposed to be a wife."

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Courtesy TLC Garrick Merrifield and Roberta

Admittedly for Dannielle, "it was a little hard at first sharing Garrick and that intimacy. I cried and I had a really hard time. But I definitely knew that it was what was supposed to be and that she was part of our life, so that secured me."

After spending nine days together on the first trip to Mexico, it "wasn't easy" for Garrick to say goodbye to Roberta.

As for the couple's two sons, they were initially nervous meeting their new mom.

"The boys, I think at first they were super nervous about Roberta. Geremiah was like, 'I only have one mom!' It's hard because she's in Brazil, she's not a part of our everyday life. They don't talk to her everyday like we do — language barrier and all that. So it is a little bit of an adjustment," says Dannielle.

Courtesy TLC Garrick and Dannielle Merrifield with their sons

And while the family is excited to welcome Roberta into their home, the reality of her becoming Garrick's wife raises fears in Dannielle, who will legally no longer have any ties to her husband or the life they've built.

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Courtesy TLC Garrick and Dannielle Merrifield

"It is kind of wild that we found a sister wife that does live halfway around the world, but we definitely wanted to start living together as soon as possible and be united as a family, so we researched different ways to bring her here and talked to an attorney and realized that the only way to get Roberta here is for Garrick to legally marry her and for her to be his wife," explains Dannielle.

The couple adds: "So there's only absolutely one option and that is for us to get a divorce."

Seeking Sister Wife premieres Monday, March 22 at 9 p.m. ET on TLC and discovery+.