If they didn’t divorce, there’s certainly something happening between them as Randall asked adult Tess to call Beth as opposed to calling her himself.
There was something strange about Beth’s acknowledging the person Randall is, and understanding he’s the type of person who can’t leave a project until he sees it through.
Her understanding that about him doesn’t mean she’ll always be okay with it, and the future timeline seemingly showed the two may have split because of it.