ask her
You should tell the other girl and both break up with your boyfriend.
I know am not a girl, but my boyfriend is my sex partner.
ummm askk her !
Ask your boyfriend. If you don't trust his answer he shouldn't be your boyfriend.
If the man has diabetes.
ask her or get somone to ask her
Does the girl know you like her? How long have you an and your boyfriend been together? And are you asking what should you do?
Well, if you are a girl whose boyfriend, who also has a boyfriend, you ask him is he is bisexual or gay. Whatever his answer, only you will know if you want to continue as his girlfriend, his friend, or if you want to move on.
The way to look at is if your boyfriend loves u he will belive u. That other girl is probably just trying to get with your boyfriend .
Make a move to be her boyfriend trust me im a girl i would know.
The most appropriate way is simply to ask her.
Just let it unravel, if your boyfriend truly loves you he'll brush aside the girl. Keep an eye on the situation, dont start rumours, this girl may not know he's taken seems she doesnt know you. Take your boyfriend aside and explain how you feel, if he cares, he'll tell the other girl whats going on.