What separates friend from “frenemy” is the presence or absence of one essential ingredient: trust.

Trust is the litmus test of any relationship, period. Without trust, there can be no (healthy) relationship. So if you want to distinguish friend or foe, start by asking yourself, “Do I trust this person? Does he or she have my back?”

http://www.metro.us/news/when-is-it-time-to-ditch-a-frenemy/tmWljn—2f16ey2AIbxHw/