have you ever heard the saying "dont shit where you sleep"?
i've actually been in a similar situation and my advice to you is cut her away... by the sounds of it your friend doesnt really know whats going on and if he finds out he'll probably feel betrayed... so my advice is if you value your friendship with your mate dont waste it over some chick...
i lost a good mate over a similar situation... we're still not talking lol... and i finally woke up to myself and realised that she's only a girl and there are plenty more out there just like her...
hope that helped
