http://www.sltrib.com/home/3805769-1...ged-to-keep-an
Is it "ex's" or "exes"?
Of all the things to give instructions about, why that? It's so weird.
Then you realize where he is coming from. He has listened to dozens (hundreds) of cases of infidelity and divorce in the church. So he has seen cases were people on facebook were connected, thus it's a big red flag. If only they hadn't been in contact with an ex. Never mind that 99% of people who maintain some contact with an ex never have an affair or do anything untoward.
But because your worldview and personal experience, suddenly this issue moves up the priority list so that it's the thing that you are focusing on in a commencement speech.