The Brown family patriarch revealed during Sunday's Sister Wives: One on One special that his marriage to Meri, 51, was "hard" from "the very beginning."
"Janelle was a blessing of dilution," said Kody, 53. "It diluted this relationship I had with Meri — and also, we are bringing more people into a problem."
According to Kody, his relationship with Meri took another hit when Janelle, 52, moved into Meri's house.
"I'm in an established relationship with somebody that I don't even get along with and then I bring somebody else in and then now it's triangulating," he said. "And then we bring Christine in and that seemed to calm it because we started having children and we seemed to have this more unified focus even though the strain was perpetual."
He continued, "This was happening from the day or the week or the month or whenever, after me and Meri had our honeymoon period. We were in the storm."
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Things eventually took a turn in Kody's relationship with Janelle.
"The family was in a bad place because Janelle moved out. She was done. She left with her mother," he revealed. "I didn't feel like she was leaving me but was leaving them because I wasn't giving her enough support. She couldn't abide being with Christine and Meri any longer. It was just too much strain on her life."
Added Kody, "She would talk to me about a comment her and her mom made about the Meri and Christine club because Janelle wasn't in it. There was just this place where Janelle didn't feel like she was fitting in."
Janelle, for her part, acknowledged that "there was conflict," but she insisted "there were really good times too."
Elsewhere in the episode, Janelle acknowledged she had a tough time opening up to Kody about her issues within the complicated dynamics in their plural marriage.
"In the very beginning, I used to try to vent to him. He'd be like, 'I can't take your side in this,'" she said. "But he's obviously taking a side now."
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Kody's separations from Meri and Janelle were recently revealed a little more than a year after Christine announced her split from Kody in November 2021. He is currently still legally married to fourth wife Robyn Brown.
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Sister Wives airs Sundays at 10 p.m. ET on TLC.