Thanks for the input, Ariakas, on the term "bi curious." Part of the reason why I was confused, is because there seems to be so many manifestations of "bi." Case in point: My husband identifies at "bi"--yet he has never had a sexual encounter with a man. He chooses to label himself bi for political reasons (he believes minorities must come forward, into the spotlight, to gain recognition and rights), but also because he, on a rare occasion, finds a man attractive. But it's never gone past the thoughts in his head. He's open to it, he's just never gotten the chance.
Thanks for the input. I now believe in bi curious. I was just judging her by my husband's standards, I think. It's interesting to me: She has had one hot sexual adventure with a woman (me), and still chooses the label straight. My husband has had zero adventures (except in his head) and embraces the label bi.