.

Since I've heard this story, I'm gonna say the following:

That sucks, but make sure she's really cheating on you before you get totally pissed off, and then if so dump her. Sorry man, know you love her, gonna be hard, I know the feeling (somewhat), dunno what else to say.

From the sounds of things, you're in high school. Girl don;t know what the hell they want in high school. Don't take it so personally and just have fun.

True that.

If I were you, I would see how open to further "experimentation" she is. Might as well have a little crazy fun if you can, you only live once.

As odd as it may seem? I have been in ALMOST the EXACT SAME situation only slightly different. The girl (Heather) had been experimenting-- only more-so after bad relationships she deemed herself asexual-- and then explicitly a lesbian-- but she fell for me-- not that I'm exactly feminine-- we just met-- and clicked- it was a long, road and she felt that she was then "Bi" -- Well there' s a key-- you CAN NOT be BI and in a RELATIONSHIP.

If you're in a relationship with a member of the same sex-- You're Gay.
If you're in a relationship with a member of the opposite sex-- You're Straight.

It's just that simple (atleast it should be in both our cases)

Well. albeit we've been in aforementioned odd cases I found the best way to survive it (despite the overwhelming inclination towards action that can end up being wholly detrimental towards what might end up being only a friendship) is to just pose the choice(relationship or no relationship)-- assert that you're not gonna play middle ground (unless either or both are down for some hot threesome action) and then just go about your business..

Look.. I know you can't stop thinking of her-- EVERYthing with Male Genitalia has been there at one point or another-- but in your best interest-- THINK ABOUT SOMETHING ELSE..

Like Hockey..

Or Flesh-eating bacteria eating someone's ears off...

Just an entertaining mental image

It sounds very much like she's just giving you enough to keep you interested, in case the whole "I like girls too" thing doesn't pan out. She's kind of got the best of everything at the moment: the whole experimenting thing (other girl), plus someone solid to fall back on (you).

For the moment, you should do nothing, until you've had a little time to think about it. Ultimately though, given your history, it sounds as though you would be better off limiting your involvment with this girl since she either doesn't know what she wants, or conversely, knows exactly how to get what she wants. Either way, you're probably going to get used and no one needs that.