'Sister Wives' Season 6 SNEAK PEEK: Robyn Possibly Pregnant With Twins, & Meri Deals With 'Rejection' Following Divorce [VIDEO]

The Brown family has gone through a lot of changes since the last season of Sister Wives, and now, in a new trailer for season 6, the family will have a hard time adjusting to the everything that's different this time around.

Kody Coming Under Fire For Alleged Favoritism

The family changed things drastically at the end of season 5 when Kody's only legal wife, Meri, filed for divorce so he would be free to marry Robyn, in an attempt to make the process of adopting her three children from her first marriage easier. However, things will become more difficult after Kody and Robyn sneak off for their new marriage and don't seem to tell anyone else-including Meri, Janelle or Christine.

"Robyn and I are getting married today," Kody says in the clip. "We're kind of eloping."

Meri Blasts Robyn's Critics

And, when the two get back and appear more loved up than ever before, it will appear to hurt Meri in more ways than she ever expected.

"Part of me feels just a little bit of rejection," she says in the clip.

And the tension in the family will only begin to get worse, after Robyn shares the news of her pregnancy.

"I'm pregnant and I'm really happy about it," Robyn says in the clip.

Kody makes thinks worse though when he starts gushing about the pregnancy-hurting his other wives' feelings.

"I just think it's twins," he says.

"REALLY?" Christine snaps back.

However, his prediction may later prove true...after Robyn is seen admitting that some news is hard to digest and could change things.

"It's a lot to take in," she says.

Now, Kody may need to work harder than ever to save his family.

"We've got to find out what's going to make this work," he says in the clip.

Sister Wives season 6 premieres Sunday, September 13 at 9 p.m. on TLC.