One of my ex-gfs with whome I was for 6 years did indeed tell it to female friends and though they never mentioned anything or tried any advances towards me, they always giggled pleasently when I was around.
My ex-wife, did tell it to her sister and mother and actually kept repeating that finally sex is not for guys to learn on her, but she can fully enjoy herself. Her sister who for a while was into black men used to giggle similarly when I was around.
I would say most if not all women do share things like that with other close females (regardless of being family or not, it seems to have to do simply with being a close female).
My present wife never admitted it openly, but didn't deny either that she talked about it to her sister and mom (and she did talk to them about great sex, so I'd think they at least implied the cause of it).