My girlfriend did this to me, I didn't like it at all because it was a problem with sex and she chose to discuss it with her friends rather than me.
What made it really bad was the fact that I found out through her typing a text message to her thread and I looked over and read "not that long".
Needless to say it is a pretty shitty feeling that fucked with me for a good month and still kind of doesa, it would have been much better if she talked to me about it first. I, as a guy don't talk to my friends about our sexual experiences unless she doesn't mind, it just isn't something I want out there.