It sounds like you know the answer to your question, but are refusing to accept it.
It's easy for G to say you're overreacting, he's got the best of both worlds and can't seem to put himself in your shoes. How would he feel if the tables were turned? If you met some hotty lesbian who put up with him just to be with you? He would probably like it about as much as you like your current situation. I doubt that he's even aware of the dynamics between you and her. He's a guy, they're kinda daft that way.
But, like it or not, it is your current situation. Although she's too chicken shit to say it explicitly, she's told you in no uncertain terms that she doesn't want to be your girlfriend. She may feel that losing you romantically means losing your friendship, as well as possibly losing your boyfriend romantically. At this point, the quickest route to recovery might be for you to take the bull by the horns and tell her you can't be in a relationship where your romantic love is not returned. At that point, you need to decide if you can still be friends with her, possibly after a cool-down period. Letting her use your love to fulfill her friendship needs is not being fair to yourself.
Also, be aware that this probably isn't about you in particular. It's not uncommon for bisexuals to fall more to one end of the spectrum than the other. You say she's had relationships with other women, but you really have no way of knowing how intimate or sexual those relationships were. It could very well be that they were experimentation, and that she's more keen on the "idea" of being bisexual than she is keen about actually being with women.
“As I am sure any cat owner will be able to tell you,
someone else putting you in a box is entirely different
from getting into a box yourself.” —bisexualbaker
Last edited by SchrodingersCat; 10-09-2012 at 01:09 AM.