I was going to list some articles proving families were separated at the border upon being caught crossing illegally, but I couldn't find a single one. I don't believe this is because they don't exist, but rather that they're being drowned by the masses of 2016-present articles.
I was able to find proof that Obama separated families that had illegal residents that were already living in the country, lots in fact. There was also a lot of 2014 articles about the surge of unaccompanied minors; apparently unaccompanied minors was the hot topic. I couldn't find a single article pre 2014.
I know for certain that fathers have always been separated from their children for the reasons I explained so I find it strange that not one article mentioned that. Actually, one article did, but it was Canadian.
I don't trust the media, I don't trust google. If you know how to search for articles from specific dates and could tell me how to do it I bet I could find you the proof.