I did have a period of very intense dreams, all of which involved my discovery of STBX's affair (in dream world) with wildy inappropriate partners (18 year old, wife of his best friend, etc). I interpreted this as workig through my both my feelings of both hetrayal and that I suddenly felt I didn't know who he was.
Your dream about your former frenemy being involved could have more to do with betrayal than competition, but who knows? I bet there's a website out there with commomn interpretations.
