Hey Mitch, good question. It seems that the "bi" label is misunderstood on both sides. Maybe this is one of the reasons that I hate labels so much :wink:.
In my opinion, it does not give you the green light to cheat. This is something that should be discussed and agreed upon in every relationship, and will be different in varying degrees with each individual situation. It can run the gaunlet all the way from strictly monagomous to completely open, and anywhere in between.
For me, one of the biggest factors in my infidelity (very ashamed of this) was my denial and the hiding of my ssa. Once that monster was in the open, It took time to see how it fit in my life. I had to decide if I could be monagomous with a woman, or if I needed an open relationship that included men.
I'm single now, so not a factor, but if I ever get in a serious realtionship again, it will be in the open, discussed, and agreed upon what works for both of us, and that agreement will be adhered to.
I'm sorry that you have had some unfortunate experiences, but it reflects that person, not their orientation.