This is what you call a pseudo-relationship, and yes, I can say that it's very hard to be in one. Parang kayo, pero hindi. The good part is that you have no obligations and no emotional stress. It only backfires when one of them falls in love, but the other partner isn't ready for a real relationship. Of course, the person who falls in love can't say or do anything about it because in this kind of relationship, you cannot expect anything from the other person and there wasn't anything to hold on to in the first place.