Thanks to a sneak peek of the show fromPeople, we now know the answer.

“Just the family dynamics.

Yeah, a lot has happened.

Ethan Plath

It’s kind of hard to say.”

“It was just toxic.”

Ethan said that this was “really hard” and “very, very frustrating” for him.

Olivia and Ethan Plath

Eventually, that frustration led to him and Olivia cutting off contact completely.

“So we don’t see them as often.

But when we do, we have fun.”