Robyn is Kody's only remaining wife.
In the drama-packed clip, Kody is seen struggling in all of his relationships apart from his one with his fourth wife, Robyn.
"I don't even know what to do with Meri," Kody admits, referencing his first wife, Meri Brown, whom he's been estranged from for years.
Though Meri has remained committed to their plural marriage despite the fact that the two have not been in an intimate relationship for almost a decade, Kody seems to not understand Meri's commitment.
"In my head, I'm really wondering why she still lives in Flagstaff," Kody admits in a confessional interview.
"There's no question, Robyn. He's done with me," Meri tells Robyn in one clip.
Even Robyn has to admit, "Kody's going to do what Kody's going to do."
Finally, Meri sits Robyn and Kody down, seemingly to tell them that she's done with being spiritually married.
"I just wanted to let you know, I'm not going to be around. It's not what I want," Meri says.
Robyn predictably bursts into tears over the news, realizing that her dreams of a plural family have been ruined.
"I wanted to sit on a porch with my sister wives, with my kids and my grandkids," she says weeping, repeating her regular sentiment of her vision for the Brown family's future.
Kody's ex, Christine Brown announced her decision to split from the polygamist in 2021. She has since become engaged to David Woolley. Janelle Brown, Kody's second wife, confirmed that they had separated in January, though their passionate fight in this trailer implies that she could be done with the marriage for good.
In the clip, Janelle tells Christine, "I'm growing and I need something different. I don't want to be married anymore."
Also in January, Meri confirmed that she and Kody had "permanently terminated" their marriage. All of this is expected to play out when the new season debuts next month.
Sister Wives season 18 premieres Sunday, August 20 at 10 p.m. ET on TLC.