Well, I don't know about all females, but I can guarantee that if anyone tried to forbid me from doing anything at all, I would either tell them outright that they were insane or just smile sweetly to their face and go behind their back and do exactly what it was they forbade me to do. Curfews are for children.
A fling could mean anything. It's a very loose term. I think the emotional betrayal here is as bad as anything physical that might have happened anyway. I would be heartbroken if my bf kissed somebody else- everything else after that would just be salt in the wound.