It's all very well saying that you want an open relationship,that may work at the moment.However,when someone comes along that you fall head over heels over,THEN someone may get hurt,and it will be you.
You don't say how old you are, but believe me time passes all too quickly, and an open relationship will(in time) result in no relationship. When you get to an age where others have a partner,and you do not, and can't find one any more.This open partner of yours is more than likely to find someone else and not come home to you.Life and relationships are more than just sex,think on that.