I hate to say this, but you should rip his head right off his neck. This type of behavior is unacceptable to me and I would not tolerate it.

I hate to say this as I know how much you care for your girl, I also care very much for my wife but I have been around the block many times in my 32 years of life and have learned a few things about females.

Are you sure your girl is not some how subconciously provoking these males to take an attraction to her? I ask cause it sounds like in your post that this is not the first time she has had a secret admirer?

I have seen some of the happiets married females be the most flirty and provocative people in the room. The easiest girls to land and get attention from are the ones that are taken and married.