Well, I have been in an open relationship and it wasn't good. I have too many trust and abandonment issues to really feel secure in one. Thus when I'm told by whomever I'm with that they want to be able to fool around, with my permission, I feel sort of taken aback and I start to feel as if they're scheming or that they'll leave me for someone else (which can happen regardless, but the situation worsens that fear). But that's a topic delving a tad off-topic for this discussion.