If the firends are just socializing that's fine... But I would make sure your WIFE knows the boundary is ZERO FLIRTING... She's made a commitment and you are holding her accountable to stick to it...

And NO former boyfriends... that is SO common a source for affairs I can't count...

Facebook is THEE NUMBER ONE SOURCE for affairs on the internet right now... even Second Life isn't as bad as facebook (and that's saying something)