Yes and i'm in one of em now :)
Yes. I had one, but it didn't turn out so well. Turned out she was already married and couldn't understand why I didn't want to be in a relationship with a married woman. Go figure.
Several. Yes. Marriages too, good ones.
Yes without doubt they have. But how long they lasted or what quality they where would vary a lot.
I was in one that became a physical relationship. 2 if sex counts as a relationship.
There are many that have.
Yes, probably, but seldom.