The challenges are about to be harder when Teen Mom OG returns -- especially for Catelynn and Tyler.

In the trailer below, the high school sweethearts openly discuss their life as husband and wife. And Nova's father, who confessed to Amber during last season's finale that he might not be the "right guy" for Cate, makes another difficult statement -- but this time, it's directed at his wife.

"If someone asked me, 'Are you happy in this marriage?' I would say absolutely not," Tyler admits, as he wipes away tears. Catelynn's response: "Do you think I'm blind to it all?"

Changing the focus: Amber happily admits that she can't think of anything else besides her "little family," while Taylor confesses to Maci that Ryan called him "in a fit of rage." And we have two new moms: Bristol Palin and Cheyenne Floyd. What can viewers expect to see from America's "most famous teen mom" and the Are You the One? and Challenge veteran? Watch Teen Mom OG Mondays at 9/8c to find out.