"If you are not interested in him, then you should tell him to the face."
"I told him I'm attached already."
"But you are still going out with him on dates."
"You are playing with people's feeling here."
"No I'm not."
"Mark my words, you'll be in deep shit soon enough."
Most would consider it wrong should someone has more than one boyfriend especially if both the boyfriends were ignorant of each other, thinking that they are the one and only. It's call an open relationship if the boyfriend knows about it. But what if he were to declare his unavailability yet went out to have flings behind the boyfriends back? Everybody except the boyfriend knew. They would probably be called slut or cheater, but that's from the boyfriend's point of view. How should people attracted to this kind of people handle themselves?
Is it by their own fault to fall willingly knowing very well the consequences? Many claims that they will never be involve with an attached guy regardless of how interested they are towards the person. But how many of them can really be this clear headed when they find themselves caught in the whirlpool?
Many says that if they cannot have it all, they would not want any at all. And that's exactly where most of them is - nothing at all. If you have proclaim such sanctity then you should have the will to uphold the solitary ritual required of you. Don't waged a vendetta against those who do.