some good questions, and I appreciate you asking things that would help me to think this out.

I have only told one male friend of mine. He commented, "I am not the only one this has happened to in the world, it happens every day to good people", and "in time the answers will come on what to do".

She told her sister and father.
Her sister wondered "Why did you even tell him (me)?"
Her father was dissapointed in her for bad judgement of what she did.

Believe it or not, the wife of the best friend involved told me that i should forgive her (my gf). But then she doesnt know if their marriage will continue, due to many factors, some related, some not.

as for the "small world". I felt it would be difficult if it was compromised. But still though how small it was, I was generally happy. Some people want a large social circle, while others chose a small group of close friends. I have been more the later.