Exactly....
I'm sorry, but she's no friend.
Friends don't do that to each other, under ANY circumstances.
She's playing you...
If nothing is going on at present (which i doubt), the past still must be addressed.
If husband sees 'no harm/no foul' with this, how to trust him IN GENERAL?
Is everyone in this scenario expected you to simply 'sit down and shut up'?
Remember, you teach people how to treat you.
If you 'teach' hubby this is ok, and acceptable way to treat you, you aren't doing anyone any favors.
Talk to them one by one, not together, but close in time, so they don't have time to get their stories together.
Hubby has prob'ly already told girlfriend, if not gf's hubby, otherwise i'd say ask her and see how far she is willing to go to 'cover up' what happened. Can she look you in the face and lie convincingly? If so, what does that tell you about the 'friendship'?
In any case, VERIFY, then trust.
(But then I'm a lawyer, and PAID to be paranoid...)
Kimberlee d.