I don't think you are at fault here!! It is her fault for coming on to a married man, her friends man at that!! And what's up with your wife? If my friend asked me for pictures of my husband I would give her a quick slap and remove her from my life!!
I have friends that my husband doesn't like, not because they fancy him but because as people they don't really get on. But because she's my friend, when she come around he goes to see his friends... then we are all happy!! (this is mutual, I never put anyone before him)
Why can't you just go and see your own friends instead of spending time with your wife's?
This is madness!!