They're supposed to be working on their relationship, but Sister Wives stars Meri and Janelle Brown continue running into familiar issues that affect not only them but their whole family.

In a preview clip for the Sunday, June 12 episode, the two are back in therapy again, after their plan to do Thanksgiving decorations together backfired on them, and with the family's upcoming vacation to Hawaii coming up, they need to find a way to handle their problems with each other in a better way.

"I hate it when she shuts down, and she hates it when I'm direct. SO what do we do?" Meri asks the family therapist, Nancy, in the clip.

Meri later explains that in addition to the drama when they worked on the Thanksgiving project, their relationship's problems go all the way back, to where their relationship as Sister Wives began, since Janelle left Meri's brother to be with Kody.

"...We both realized we do things completely different. But we also have years of reacting to one another's differences," Meri explains in the clip.

Talk will quickly then turn to the upcoming trip to Hawaii, and the idea that the two women could do an activity together will be broached by Janelle, who will suggest she and Meri research some ideas.

"I don't know, maybe we'll have to get on a computer and find some goofy thing that would make sense," Janelle says.

Meri seems hesitant at first however, since she isn't really sure what they could honestly do together that would make sense.

"...I have no idea what we could do together," she says. "Maybe we can go to the beach and build a sandcastle together?"

However, Janelle will have come conditions as well, since Meri has an different idea of what could be fun than she does.

"I am not going to do some dare devil thing with you because that's not going to be filled with emotion," she says. "That will be terror."

Sister Wives airs Sundays at 8 p.m. on TLC.