Is it the norm for attractive women to sleep around?

Not 'sleep around' no. But it makes logical sense that they will get more attention, more men asking them for their time etc. With more opportunities in anything people are more likely to take them or be involved with them at least (such as attractive girls usually making the effort to look *stunning*) but not necessarily act upon it. It's just a strong point of theirs and everyone tends to play to their strong points.

Sometimes attractive people enjoy the attention and have fun with it, yes. But it's not just about women. Gorgeous women tend to be insecure very commonly but i've rarely met a handsome man who hasn't milked his power for much of what its worth.

She is a *****

More often that most folks realize - but not every attractive woman does so.

If they aren't attached to someone, they are just having fun. No big deal

Yes its actually more common nowadays then in the past. One reason why is because there are more women in the work force and they don't want to take the time to form relationships.